This was CNBC's live blog tracking developments on the war in Ukraine on Monday. See here for the latest updates. 

Russia's President Vladimir Putin attempted to justify his unprecedented invasion of Ukraine on "Victory Day" — one of the most important events on the country's national calendar.

The West was "preparing for the invasion of our land, including Crimea," Putin said without providing evidence, according to a Reuters translation. He added that NATO was creating threats at Russia's borders.

Russia had amassed some 190,000 troops on its borders with Ukraine in the weeks before its invasion. There was little evidence of military aggression from Ukraine toward Russia, and Moscow's claims to the contrary were seen by many as a pretext for justifying the invasion.

Meanwhile, dozens are feared dead after a school in the Luhansk region in eastern Ukraine was hit by Russian shelling. Ukraine's President Volodymyr Zelenskyy said that 60 people died in the attack.

At least 1 million Ukrainians were 'forcibly relocated' to Russia, says rights official

At least a million Ukrainians have been "forcibly relocated" and sent to Russia, according to a Ukrainian human rights official cited by NBC News.

"Not only are the occupiers hiding their crimes, but also relocating everyone they deem unreliable," said Lyudmyla Denisova, Ukraine's ombudsman for human rights.

"We have proof that forceful deportation was prepared beforehand," Denisova said, according to NBC News. "There are facts that confirm that Russia had directives for their districts on how many Ukrainians and where to deport them."

NBC News and CNBC were not able to confirm those claims.

An estimated 20,000 Ukrainians are in "filtration camps," with most being sent to Russia, while the fate of the rest remains unknown, Denisova added, NBC News said.

Last month, the United Nations Human Rights Monitoring Mission in Ukraine documented about 109 cases of suspected detention or enforced disappearances among civilians since the invasion began.

However, local officials said the figure does not represent the tens of thousands of Ukrainians who have been deported via "filtration camps."

— Chelsea Ong

Ukraine's prime minister says the U.S. steel tariff suspension came together in a matter of weeks

Just hours after the U.S. announced it would suspend tariffs on Ukrainian steel for a year, Ukrainian Prime Minister Denys Shmyhal expressed his appreciation for the speed with which the Biden administration moved on the issue.

Shmyhal said he first spoke about the tariffs with Commerce Secretary Gina Raimondo when he visited Washington on April 21.

Less than 3 weeks later, the U.S. announced that the current 25% tariff would not be applied to steel from war-torn Ukraine for at least a year.

The tariff suspension is the latest example of the White House and federal agencies slashing bureaucratic red tape in Washington in order to get money, weapons and humanitarian supplies to Ukraine.

--- Christina Wilkie

Nearly 6,000 Ukrainians approved to enter the U.S. through Biden admin's Uniting for Ukraine website

The Department of Homeland Security has approved nearly 6,000 Ukrainians to enter the U.S. through an online application system that lets them gain legal authorization to fly to U.S. airports and then stay with Americans who have agreed to sponsor them, the agency said Monday. 

The online portal, known as Uniting for Ukraine, launched on April 25 as part of President Joe Biden's stated goal to bring 100,000 people fleeing Russia's deadly invasion to the U.S.

The launch of the website meant the closure of a popular but dangerous and illegal route many Ukrainians had taken via the U.S.-Mexico border, where, after entering Mexico on a tourist visa, they were transported from camps in Tijuana into California. After April 25, U.S. Border Patrol officers began turning back Ukrainians attempting to cross the southern border. 

Read the full NBC News story here.

— Julia Ainsley, NBC News

Biden shifts course, calls on Congress to pass standalone Ukraine aid with no Covid funds

President Joe Biden has very publicly shifted course in his quest to pass a $33 billion emergency funding package for Ukraine through Congress.

"Previously, I had recommended that Congress take overdue action on much needed funding for COVID treatments, vaccines and tests, as part of the Ukraine Supplemental bill," Biden said in a statement.

Recently, however, Biden says he was informed that Republicans in Congress are not prepared to vote to pass a Covid bill anytime soon.

Given the reality of the situation, linking the two funding requests — as he had initially proposed — would have in practice meant slowing down the desperately needed money for Ukraine in order to give Congress time to debate the Covid funding.

"We cannot afford delay in this vital war effort," Biden said. "Hence, I am prepared to accept that these two measures move separately, so that the Ukrainian aid bill can get to my desk right away."

Biden's change of strategy was also adopted by Democratic leaders in Congress, who have said they are prepared to move quickly on a standalone Ukraine bill. It is expected to be relatively easy to pass with bipartisan support.

— Christina Wilkie

Biden has about $100 million in military aid to allocate to Ukraine until Congress passes new funding, Pentagon says

The Biden administration has about $100 million in military aid left to allocate to Ukraine before it needs Congress to approve more funding, Pentagon spokesman John Kirby said.

He referenced so-called presidential drawdown authority, which allows President Joe Biden to transfer excess weapons from U.S. arsenals without congressional approval.

"We think and again, this is an estimate, but by the third week of the month, we expect to utilize all of that," he added.

Last week, the Biden administration announced a new weapons package for Ukraine worth $150 million. The latest military aid package, the ninth security assistance installment, brings the U.S. military aid commitment to $3.8 billion since Moscow invaded its neighbor in late February.

Last month, Biden requested $33 billion from Congress after he exhausted his remaining drawdown authority. He said that for Ukraine to succeed against Russia, the U.S. and its allies must continue to move weapons and ammunition into the country.

— Amanda Macias

Ukrainian servicemen survey destroyed Russian equipment outside Kharkiv

EDITOR'S NOTE: Some images depict death.

Ukrainian servicemen survey destroyed Russian equipment on the outskirts of Kharkiv.

— Diego Herrera Carcedo | Anadolu Agency | Getty Images

Ukraine's PM and European Council president hold part of their meetings in an air raid shelter

Ukrainian Prime Minister Denys Shmyhal said his meeting with European Council President Charles Michel in Odesa was interrupted by air raid sirens warning of a Russian missile attack near the city.

In response to the sirens, the two dignitaries moved their official event to a dimly lit underground air raid shelter and continued their conversation. Shmyhal posted a photo of himself in the bunker with Michel on Twitter.

Images like this one have helped Ukrainian leaders create a powerful narrative of a government whose officials are finding brave and creative ways to operate in a war zone, despite being in near constant danger.

--- Christina Wilkie

Biden signs bill that aims to streamline U.S. military aid to Ukraine

President Joe Biden signed a bill that will streamline the lengthy process of supplying Ukraine with the military equipment needed for the fight against Russia.

Biden's signature on the Ukraine Democracy Defense Lend-Lease Act of 2022 will make it easier for the U.S. to lend or lease military aid to allies affected by Russia's invasion of Ukraine. Biden already has some power to lend or lease equipment, but the legislation he will sign into law will ease some of the requirements for doing so.

Under the measure, Ukraine can request streamlined transfers of U.S. weapons and other security assistance. The U.S. will get guarantees that the country will replace or reimburse the assets at a later date.

— Amanda Macias

Global sanctions are affecting Russia's ability to resupply troops, U.S. Defense official says

Western sanctions have hurt Russia's ability to resupply its forces with weapons and equipment in its fight against Ukraine, a senior U.S. Defense official said.

"It's definitely beginning to bite into his industrial defense capability," said the official, who spoke on the condition of anonymity in order to share updates on the ongoing war in Ukraine.

The official said that Russian forces "have blown through a lot of their precision-guided munitions."

"We do believe that the sanctions and the export controls particularly when it comes to components to electronic components, have had an effect on the Russian defense industrial base and their ability to resupply precision-guided munitions," the official added.

In the weeks since Russia's Feb. 24 invasion of its ex-Soviet neighbor, Washington and its allies have imposed rounds of coordinated sanctions that have vaulted Russia past Iran and North Korea as the world's most-sanctioned country.

— Amanda Macias

Elon Musk spars with Russian space head over SpaceX providing Starlink dishes to Ukraine

Elon Musk sparred with Russian state space agency Roscosmos' leader via Twitter on Sunday, with the SpaceX CEO responding to Dmitry Rogozin's accusation that the company is supplying "fascist forces in Ukraine" with Starlink satellite communications equipment.

"The word 'Nazi' doesn't mean what he seems to think it does," Musk said in a tweet, with a screenshot of Rogozin's statement.

Rogozin had declared that Musk would "be held accountable like an adult" for supplying Starlink dishes to Ukraine.

A few minutes after his initial response, Musk tweeted again:

"If I die under mysterious circumstances, it's been nice knowin ya," he said.

Rogozin often makes outlandish public threats that haven't come to pass, such as his repeated declarations that Russia will withdraw from its partnership on the International Space Station. But he has followed through on others, such as when Roscosmos held hostage satellites of U.K. company OneWeb, which has since led OneWeb to partner with SpaceX and others to reach orbit.

– Michael Sheetz

U.S. will suspend 25% tariffs on Ukrainian steel for one year

The United States will suspend Trump-era tariffs imposed on Ukrainian steel for one year, Commerce Secretary Gina Raimondo announced. Through the move, the U.S. aims to bolster one of Ukraine's key domestic industries while the country defends itself against the Russian invasion.

"We can't just admire the fortitude and spirit of the Ukrainian people—we need to have their backs and support one of the most important industries to Ukraine's economic well-being," Raimondo said in a statement announcing the suspension.

Before the war, Ukraine's steel industry employed 1 out of every 13 Ukrainians. But it is unclear how much of that industry is still operating, and how much the steel plants still in production are exporting as Ukraine races to manufacture weapons for its armed forces.

During peace time, base metals like steel are far and away the top export product from Ukraine to the United States. In 2019, Ukraine exported roughly $780 million worth of base metals to the U.S., a figure that represented 59% of all its U.S. exports that year, according to Commerce Department data.

Until the announcement, Ukrainian steel exported to the U.S. was subject to a 25% import duty.

— Christina Wilkie

Nearly all U.S. howitzers have arrived for the fight in Ukraine, U.S. Defense official says

Almost all of the 90 howitzers pledged in the last two U.S. security assistance packages have arrived for the fight in Ukraine, a senior Defense official confirmed.

The official, who spoke on the condition of anonymity in order to share updates on the ongoing war in Ukraine, declined to say where and how many howitzers have been used in battle. The official said that more than 60% of the howitzer artillery rounds have also been transferred to Ukrainian forces.

The official said that U.S. forces have trained more than 300 Ukrainian soldiers on the BAE Systems M777 lightweight 155mm howitzer. The official said that another 50 Ukrainian troops will train alongside U.S. troops.

The training is ongoing at an undisclosed location outside of Ukraine.

— Amanda Macias

Russia has made 'virtually no progress' in southern Ukraine, U.S. Defense official says

Russian forces have made "very limited progress" in the ground offensive against Ukraine in the past week, a senior U.S. Defense official said.

"Like single-digit kilometer kind of progress because the Ukrainians keep pushing them back," added the official, who spoke on the condition of anonymity in order to share updates on the ongoing war in Ukraine.

The official said that Russian troops specifically made "virtually no progress in the south," but continue to strike portions of the country from the sky.

"They are still launching weapons into Mariupol and other airstrikes, long-range missile fires we've seen in and around Odesa and then unsurprisingly, in the northern part of the Donbas area," the official said.

For weeks, Russian forces have faced logistical issues, supply shortages and morale challenges. The Pentagon has indications that in the Donbas region, some mid-grade Russian officers have refused orders, the official said.

— Amanda Macias

Zelenskyy says Ukraine has completed second part of EU membership application

Ukrainian President Volodymyr Zelenskyy informed European Commission President Ursula von der Leyen that Kyiv completed the second part of its application for European Union membership.

Zelenskyy said he showed the second part of a completed questionnaire to von der Leyen over a video call. Last month, Zelenskyy submitted the first part of the application.

"Thank you for the clear signals of support on this important path for us," Zelenskyy wrote on the Telegram messaging app.

— Amanda Macias

Hungary’s Orban — a longtime Putin ally — stalls Europe’s Russian oil embargo

The European Union is struggling to approve a sixth round of sanctions against Russia with a few nations pushing back on a proposed oil embargo.

Hungary has been the EU's most vocal opponent on the oil ban. Prime Minister Viktor Orban — a longtime ally of Putin — has said that ending Russian oil purchases would be an "atomic bomb" on Hungary's economy.

The impasse is preventing the EU from approving the broader package of sanctions.

Read the full story here.

— Silvia Amaro

Photos show Russia’s massive ‘Victory Day’ parade in Moscow

Russia held its "Victory Day" military parade on Monday to mark the 77th anniversary of the Soviet Union's defeat of Nazi Germany in World War II.

Over 65,000 people were expected to take part with 2,400 armament and material units.

The parade this year comes against the backdrop of Russia's unprovoked invasion of its neighbor Ukraine, which has seen thousands killed and caused more than 5 million people to flee the country.

See more photos here.

— Matt Clinch

UN says 3,381 killed in Ukraine since start of war, warns death toll is likely higher

The United Nations has confirmed 3,381 civilian deaths, including at least 235 children, in Ukraine since Russia invaded its ex-Soviet neighbor on Feb. 24.

The agency also reported 3,680 civilian injuries in the conflict so far.

The Office of the UN High Commissioner for Human Rights said the death toll in Ukraine is likely higher, because the armed conflict can delay reports.

The international body said most of the civilian casualties recorded were caused by the use of explosive weapons with a wide impact area, including shelling from heavy artillery and multiple launch rocket systems, as well as missiles and airstrikes.

— Amanda Macias

Russian ambassador to Poland hit with red paint in Warsaw

Russia's ambassador to Poland was splattered by red paint thrown at him by protesters opposed to the war in Ukraine, preventing him from paying respects on Monday at a Warsaw cemetery to Red Army soldiers who died during World War II.

Ambassador Sergey Andreev arrived at the Soviet soldiers cemetery to lay flowers on Victory Day, which marks the defeat of Nazi Germany by the Allies. The holiday was celebrated with pomp in a parade at Red Square in Moscow.

As he arrived at the Soviet Soldiers Cemetery in the Polish capital, Andreev was met by hundreds of activists opposed to Russia's war in Ukraine.

The protesters carried Ukrainian flags and chanted "fascist" and "murderer" at him, while some were dressed in white sheets smeared with blood, symbolizing the Ukrainian victims of Russia's war. Other people in his entourage were also seen splattered with what appeared to be red paint.

— Associated Press

'We will win': Ukraine's leader says as he commemorates World War II sacrifice

Ukraine President Volodymyr Zelenskyy has reiterated that his country will defeat Russia's invasion and will not cede any of its territory to Moscow.

Speaking on Monday as Russia held its annual "Victory Day" military parade, Zelenskyy commemorated the deaths of more than eight million Ukrainians in World War II and said Kyiv would not allow Moscow to appropriate the victory over Nazism just for itself.

"On the Day of Victory over Nazism, we are fighting for a new victory. The road to it is difficult, but we have no doubt that we will win," Zelenskyy said, Reuters reported.

As Russia's leader Vladimir Putin invoked the Soviet Union's defeat of Nazi Germany and likened that triumph to Russia's invasion of Ukraine, Zelenskyy said "there are no shackles that can bind our free spirit. There is no occupier who can take root in our free land. There is no invader who can rule over our free people. Sooner or later we win," he said.

— Holly Ellyatt

Russia's Putin blames the West for Ukraine invasion in annual 'Victory Day' speech

President Vladimir Putin told a crowd in Moscow that Russian forces in Ukraine are "defending the motherland" as he sought to defend the Kremlin's unprovoked onslaught.

Speaking at Russia's annual "Victory Day" parade, Putin said the country's invasion of Ukraine had been necessary because the West was "preparing for the invasion of our land, including Crimea." He provided no evidence for his claims.

Read more on Putin's speech here.

— Sam Meredith

Putin 'mirroring fascism' of 77 years ago, UK's Wallace says

Russian President Vladimir Putin and his generals are mirroring the fascism and tyranny of 77 years ago and their invasion of Ukraine dishonours its military past, British Defence Secretary Ben Wallace said on Monday.

In a speech to coincide with Russia's Victory Day parade commemorating the end of the World War Two, Wallace said the Russian generals were as complicit as their president, and should face court martial.

"Through the invasion of Ukraine, Putin and his inner circle of generals are now mirroring fascism and tyranny of 77 years ago, repeating the errors of the last century's totalitarian regime," he said.

— Reuters

Russian forces continue to storm Azovstal steel plant complex, Mariupol official says

An adviser to the mayor of Mariupol says Russian forces have continued their attack on Ukraine's besieged Azovstal steel plant complex shortly after all women, children and elderly were evacuated.

"As expected, after the departure of the UN column outside the Donetsk region, the occupiers began storming Azovstal," Petro Andriushchenko said, according to a translation.

"In particular, an attempt was made to break through the bridge, which was used for the evacuation. Unsuccessful," he added.

— Sam Meredith

Putin claims the West was 'preparing for the invasion of our land'

Russia's President Vladimir Putin has attempted to justify his unprecedented invasion of Ukraine on "Victory Day" — one of the most important events on the country's national calendar.

The West was "preparing for the invasion of our land, including Crimea," Putin said without providing evidence, according to a Reuters translation. He added that NATO was creating threats at Russia's borders.

Speaking before a massive parade of troops, tanks and military hardware in Moscow, Putin also doubled down on Russia's strategy of focusing on the eastern Donbass region.

"You are fighting for your Motherland, its future," he said to pro-Russian separatist fighters, based in the Donetsk and Luhansk areas of the region.

After initially targeting the north, east and south of Ukraine in its invasion, Russia switched its strategy and objectives in late March after making few territorial gains.

It announced it was withdrawing from areas around Kyiv and the north and would instead focus on the "liberation" of the Donetsk and Luhansk areas.

Russia launched an unprecedented invasion of its neighbor Ukraine on Feb. 24, after amassing some 190,000 troops on the borders in the weeks before. There was little evidence of military aggression from Ukraine toward Russia, and Moscow's claims to the contrary were seen by many as a pretext for justifying the invasion.

— Katrina Bishop

Russia prepares for 'Victory Day' parades across the country

Russia is set to hold its massive "Victory Day" military parades on Monday, with 28 Russian cities set to hold military marches to mark the 77th anniversary of the Soviet Union's defeat of Nazi Germany in World War II.

Over 65,000 people will take part in them and about 2,400 armament and material units will be presented, Russia news agency Tass reported. The largest parade is held in Moscow and is expected to be presided over by President Vladimir Putin.

In a recorded speech to Group of Seven leaders Sunday, Ukraine's President Volodymyr Zelenskyy said that while May 8 (Victory in Europe Day) "was a key day of remembrance for all the victims of World War II, for the fragility of peace and the inadmissibility of any anti-humanist regimes. But what is remembrance for others today, for our people is, unfortunately, just news, every day."

He said a Russian bomb had killed 60 civilians in a village in Luhansk, saying the victims were hiding from shelling in a school which was attacked by a Russian air strike.

He said Russia was imitating "precisely the evil that the Nazis brought to Europe."

— Holly Ellyatt

Ukraine ambassador to the U.S.: 'We are preparing for everything' ahead of Russia's 'Victory Day'

Ukraine's Ambassador to the U.S. said Sunday that the nation is making preparations ahead of Russia's Victory Day.

"We know that there are no red lines for the regime in Moscow, so we are preparing for everything," Oksana Markarova said Sunday on CBS' "Face the Nation."

"We can count that Putin and imperialistic Russia will do everything bad they can possibly try to do. The question is, are we all prepared — the civilized world — to do everything possible to defend our democracy and freedom," she said.

Monday's "Victory Day" is a key date for Russia. It marks the then-Soviet Union's defeat of Nazi Germany at the end of World War II in 1945.

Russian President Vladimir Putin is expected to make a speech tomorrow, with massive military parades through the center of Moscow also expected.

— Pippa Stevens, Holly Ellyatt

Jill Biden pays surprise visit to Ukraine, meets first lady

U.S. first lady Jill Biden made an unannounced visit to western Ukraine, holding a surprise Mother's Day meeting with the nation's first lady, Olena Zelenskyy, as Russia presses its punishing war in the eastern regions.

Biden traveled under the cloak of secrecy, becoming the latest high-profile American to enter Ukraine during its 10-week-old conflict with Russia.

Her visit follows recent stops in the war-torn country by U.S. House Speaker Nancy Pelosi and other members of Congress, as well as a joint trip by U.S. Secretary of State Antony Blinken and U.S. Defense Secretary Lloyd Austin to meet with President Volodymyr Zelenskyy in Kyiv.

The first lady traveled by vehicle to the town of Uzhhorod from a Slovakian village that borders Ukraine.

— The Associated Press

Dozens feared dead after bomb hits school in Luhansk region

Serhiy Haidai, the governor of the Luhansk region, said Sunday that at least two people had died after the bombing of a school.

Haidai said, according to a Reuters translation, that the bombing occurred Saturday afternoon where 90 people had been sheltering. He said 30 had been rescued with around 60 still likely to be under the debris and feared dead.

Luhansk is one of the two regions that make up the Donbas — in the east of Ukraine — where Russian troops are now concentrating their efforts.

The Associated Press added that the school was located in the village of Bilogorivka. Rescue work is ongoing.

NBC News was not able to independently verify the reports.

"The fire was extinguished after nearly four hours, then the rubble was cleared, and, unfortunately, the bodies of two people were found," Haidai wrote on the Telegram messaging app, according to Sky News.

"Thirty people were evacuated from the rubble, seven of whom were injured. Sixty people were likely to have died under the rubble of buildings." 

—Matt Clinch

Read CNBC's previous live coverage here:

Jill Biden pays surprise visit to Ukraine; 60 feared dead in Russian bombing of Ukrainian school