This was CNBC's live blog tracking developments on the war in Ukraine.

U.S. aid to Ukraine is running low and will soon expire, the White House warned, stressing that it has just enough pre-authorized funding for one more aid package this year before the administration needs to get Congressional approval again.

That task has become increasingly difficult as a growing number of Republicans block Ukraine aid, demanding that Biden put more focus and resources toward domestic issues like securing America's southern border.

Ukrainian President Volodymyr Zelenskyy nonetheless told a press conference Tuesday afternoon he was confident the U.S. would "not let us down" and more aid would come "very soon." He also expressed optimism the European Union would approve the 50 billion-euro ($54 billion) financing package that was blocked by Hungarian Prime Minister Viktor Orban last week.

Ukraine's top general earlier in the day issued what appears to be clear criticism of Zelenskyy over difficulties in recruiting new soldiers.

Meanwhile, the Collective Security Treaty Organization, a Russian-led military alliance of post-Soviet countries, announced plans to carry out seven drills in 2024, Russian state outlet Tass reported.

On Monday, the EU approved its 12th package of sanctions on Russia, and Russian President Vladimir Putin registered his candidacy for his country's 2024 elections.

Zelenskyy 'confident' US and EU funding will come through

Ukrainian President Volodymyr said he was confident the United States and European Union would agree to provide funding packages that are currently stuck in limbo due to political opposition.

Zelenskyy gave a wide-ranging press conference Tuesday afternoon in which he took a host of questions from reporters for more than an hour.

"I am confident the United States will not let us down and what we have agreed will be agreed in full," he said, according to a live BBC translation. "As for the European Union, the stakes were very high, we have acquired one victory as to the EU, as for the 50 billion [euro financing package] I am confident we can achieve all of that."

Zelenskyy separately said military leaders had asked for an additional 450,000 to 500,000 people to be mobilized into the army, but stressed that he required more arguments and a "comprehensive" plan before approving the costly move.

In response to a question about the difficulties faced by Ukraine this year, he stressed that Russia had failed to achieve its aims.

He said Ukraine had seen a "big victory on the Black Sea" where it was able to trade again and Russian vessels had been withdrawn.

Asked whether Ukraine was beginning to lose the war, he replied: "No."

However, he did discuss the shortage of items including artillery shells, ammunition for air defense and anti-tank grenades.

— Jenni Reid

Russia could open second front, Belgium's army chief says

Europe must show that it is ready to defend itself if Russia opens a second front beyond Ukraine, head of Belgium's armed forces Michel Hofman told broadcaster VRT on Tuesday.

"We see that Russia has switched to a war economy. I think we would be right to be worried. The language used by the Kremlin and by President Vladimir Putin is always ambiguous," Hofman said, in comments published in English.

"It is by no means out of the question that they might open a second front at some time in the future. Either in the south, in Moldova or the Baltic States," he said.

The Baltics consist of NATO and European Union members Estonia, Latvia, and Lithuania. All three have a border with Russia.

Moldova borders Ukraine to the south, along the conflict-hit Odesa region. It is not a member of NATO or the EU, but last week formally began accession talks with the latter. Moldovan Prime Minister Dorin Recean said on Monday that the country needed an upgraded anti-aircraft defense system to counter threats from Russia.

"They have already shown that they have the will to attack a neighbor. We have to see that we have the capacity to prevent this happening again and show the will that we are prepared to counterattack if necessary," Hofman said, as reported by VRT.

— Jenni Reid

UK's Cameron pledges Ukraine support for 'as long as it takes'

The United Kingdom will continue supporting Ukraine for "as long as it takes," Foreign Secretary David Cameron said during a press conference with his Italian counterpart Antonio Tajani on Tuesday.

Cameron said the conflict had so far seen three "acts" — the first, Russia's full-scale invasion and failure to take Kyiv; and the second, the efforts of Ukrainians to take back half the land Russia had captured.

"I accept that act three has been more of a stalemate on land, but it has been a huge success on the Black Sea where Russia has been pushed back. Act four is still to be written, and it's up to us to write it," he said.

Ukraine's land-based counteroffensive operation, launched in June along a long frontline across the east and to the south, made much slower than expected progress ahead of the harsh winter.

The U.K. has been the second largest provider of military assistance to Ukraine during the war, pledging around £4.6 billion ($5.85 billion), government-provided figures show. The United States has provided some $46.3 billion, according to the Council of Foreign Relations.

Cameron added that Ukraine's allies, including the U.K., Italy, Germany, France and the U.S., outranked Russia 25 to one. "We just need to make that economic strength pay and we can make sure Putin loses, and it's essential that he does," he said.

Italy's cabinet on Tuesday passed a decree allowing the continued supply of "means, materials and equipment" to Ukraine in its war effort, Reuters reported. The decision now goes to parliament.

While U.S. aid now hangs in the balance, Ukraine also received a blow last week when Hungarian Prime Minister Viktor Orban blocked the approval of a 50 billion-euro ($54 billion) EU package in financial aid for the country.

— Jenni Reid

Putin says Russia does not seek fight with Europe and NATO

Russia does not intend to fight with Europe and NATO and is prepared to negotiate with the West on Ukraine based on Moscow's own interests, Russian President Vladimir Putin said.

Speaking at a meeting of the board of the ministry of defense, Putin once more struck a tone of vehement criticism against the U.S., whom it accused of concern over Moscow's increasing rapprochement with Europe, according to Google-translated comments reported by state news outlet Tass.

Putin has repeatedly put the blame for Moscow's invasion of Ukraine at the feet of the West broadly and the U.S. specifically, painting Kyiv's NATO membership bid as a threat to Russia.

The Russian head of state went on to stress the positive outcomes of Moscow's previous appropriation of Ukrainian land in the grander scheme of European politics.

Referencing the events of 2014, Putin said that a "bloodbath" would have taken place if Russia had not annexed the peninsula of Crimea, then part of Ukraine, saying Moscow was the only guarantor of the sovereignty and territorial integrity of Ukraine.

— Ruxandra Iordache

Turkey's Erdogan seeks to bring Putin back to negotiations over grain corridor

Turkish President Recep Tayyip Erdogan plans to urge his Russian counterpart Vladimir Putin to return to the negotiations table over the Black Sea grain initiative that lapsed in July.

"We will soon have a meeting with Russian President Mr. Vladimir Putin and say, 'Let's do whatever we can to operate the Grain Corridor,'" Erdogan said, according to Google-translated comments reported by Turkish news outlet Haberturk. "Hopefully, we will continue on our way by getting positive answers from him.

First inked in July 2022, the U.N.-brokered Black Sea Grain Initiative sought to allow the circulation of exports of Ukrainian and Russian agricultural and fertilizer goods, in a bid to abate a global food shortage after Moscow's invasion of Ukraine. The deal was repeatedly renewed in short increments, before Russia allowed it to lapse, citing discontent with perceived restrictions on the dispatch of its own exports. Turkey played a significant part in mediation.

Since the collapse of the Black Sea Grain Initiative, Kyiv has set up what it calls a temporary humanitarian corridor, attempting to resuscitate its export flows without Russian approval. The U.N. has said that efforts to achieve a new agreement over a broader Black Sea corridor should continue despite this temporary Ukraine-led arrangement, according to Reuters.

— Ruxandra Iordache

Putin touts Russia's nuclear capabilities

Russian leader Vladimir Putin has stressed the importance of nuclear capabilities, while accusing the West of carrying out a "hybrid war" against Moscow.

The role of the nuclear triad has grown significantly, Putin said during a meeting of the board of the Russia's defense ministry, according to a Google-translated Telegram update from state news agency Tass.

A nuclear triad refers to three-pronged military structure that combines land-based ballistic missiles, submarine-launched projectiles and strategic bombers. Only five countries possess a nuclear triad.

Russia has upgraded the level of modern technology in its strategic nuclear forces to 95%, Putin added.

While praising his country's military capabilities, Putin nevertheless said that Russian forces must also increase the number of their drones and satellites and improve their air defense, acknowledging that Moscow's troops have experienced challenges in combat against small drones.

He went on to accuse that Western forces pledged not to expand the NATO coalition eastward but "lie shamelessly, at every step" and wage a "hybrid" war against Russia.

— Ruxandra Iordache

Russia says it will 'not leave unanswered' the build-up of NATO military on its border

Russia will "not leave unanswered the build-up of NATO military potential on our border," Russian Foreign Ministry spokesperson Maria Zakharova said, following the newly signed defense agreement between Finland and the United States.

Under the pact, the Helsinki grants the U.S. military access across Finnish territory down to its border with Russia. Finland is the latest country that adhered to the NATO alliance earlier this year, abandoning a long-held position of political neutrality in the wake of Russia's invasion of Ukraine.

The ambassador of Finland to Moscow was summoned to the Russian Foreign Ministry and told that Moscow will "take the necessary measures to counter aggressive decisions Finland and its NATO allies," Zakharova added in Google-translated comments on Telegram.

Russia has historically attributed its war in Ukraine to a perceived threat against Moscow's own interests and sovereignty, as a result of Kyiv's aspirations to join the NATO military coalition.

— Ruxandra Iordache

January-November exports of Ukrainian goods down by 19.3% year on year

The volume of Ukrainian goods exported in the first 11 months of this year was 19.3% below the same period of 2022, as a result of sea blockades and Russian attacks against export transport logistics, Yulia Svyrydenko, Ukrainian minister of economy, said on social media.

If ongoing efforts to bring exports out by sea through the temporary grain corridor continue, the total volume of Ukrainian exports of goods and services could grow by 9.0% in 2024, 19.4% in 2025, and 20.6% in 2026, she added.

The Ukrainian economy has been sharply affected by the Russian invasion, which has decimated critical production and transport infrastructure, as well as choked sea exports of agricultural goods after the collapse of the Black Sea Grain Initiative.

— Ruxandra Iordache

Russia will circumvent diamond ban, Kremlin says

Russia possesses and will implement "options to circumvent EU sanctions on diamonds," Kremlin spokesperson Dmitry Peskov said Tuesday, in Google-translated comments carried by Russian state news agency Tass on Telegram.

On Monday, the EU agreed its 12th package of sanctions against Moscow for its war in Ukraine, imposing a ban on the direct or indirect import, purchase or transfer of diamonds that originate in Russia, are exported by the country or transit the nation. The prohibition applies to both natural and synthetic diamonds, alongside diamond jewelry.

An indirect import ban on Russian diamonds processed in third countries will be phased in between March 1 and Sep. 1 next year.

— Ruxandra Iordache

There have been 105 clashes between Russia and Ukraine over the past day, Ukraine says

A total of 105 combat engagements took place between Ukrainian and Russian forces over the past day, the General Staff of the Armed Forces of Ukraine said in a Facebook update.

The clashes included one rocket and six aerial strikes, as well as 62 instances of shelling, all carried out by Russia, the update said.

The General Staff of the Armed Forces of Ukraine said that civilians were killed and injured as part of the violence without supplying tallies, while adding that private residential infrastructure also sustained damage.

More than 140 settlements in the Chernihiv, Sumy, Kharkiv, Luhansk, Donetsk, Zaporizhia Kherson and Mykolaiv oblasts came under artillery fire, the update added.

CNBC could not independently verify developments on the ground.

— Ruxandra Iordache

Russian-led military bloc, Collective Security Treaty Organization, to hold 7 drills in 2024

The Collective Security Treaty Organization, a Russian-led military alliance of post-Soviet states, announced its plans to carry out seven joint drills in 2024, its Secretary General Imangali Tasmagambetov told Russian state outlet Tass.

The military bloc is made up of six ex-Soviet countries: Russia, Belarus, Kazakhstan, Kyrgyzstan, Tajikistan and Armenia.

Similar to NATO's Article 5, which stipulates that an attack on one member signifies an attack on all, Article 4 of the CSTO's Collective Security Treaty affirms that an act of aggression against one member is seen as an attack on all members. CTSO signatories are not allowed to join other military alliances.

— Natasha Turak

Ukraine's top general criticizes Zelenskyy

Ukraine's top general, Armed Forces Commander-in-Chief Valerii Zaluzhnyi, criticized Ukrainian President Volodymyr Zelenskyy in an interview with local press while speaking about his country's military recruiting abilities. 

Zelenskyy fired all of Ukraine's military recruitment heads in an anti-corruption crackdown in August. When asked if this had affected recruiting, Gen. Zaluzhnyi lamented the move, saying:

"They were professionals, they knew how to do it, but they are gone."

As for the country's new recruiting strategy, he said, "It's still a little early to evaluate recruiting, and as for the issues of mobilization, it's not just that it needs to be strengthened, but returned ... to the framework that worked before."

Reports on the ongoing heavy fighting in Ukraine's east describe exhausted soldiers being injured and killed at high rates and military commanders struggling to find replacements for them.

— Natasha Turak

U.S. aid to Ukraine will soon expire, White House warns

The Biden administration has enough previously authorized funding for just one more military aid package to Kyiv for 2023 before it has to get Congressional approval for new packages, National Security Council spokesperson John Kirby told press Monday evening.

"We have... one more aid package here before our replenishment authority dries up," Kirby said. The replenishment system is how the Department of Defense replaces the weapons it donates to Ukraine and must be approved by Congress.

That approval is proving more and more difficult to come by as many hardline Republicans refuse to approve new funding, angry at what they say is Biden putting Ukraine ahead of domestic issues like border security.

— Natasha Turak

Putin submits documents to run for Russian 2024 presidential election

Russian President Vladimir Putin submitted documents to the country's Central Election Commission to register his candidacy for the 2024 presidential election.

"He submitted them," Kremlin spokesperson Dmitry Peskov said of Putin and the documents, confirming the news to Russian state media. The president was nominated by a group of prominent members of the ruling United Russia party as well as famous actors, athletes and other Russian celebrities.

Putin has been either prime minister or president of Russia continuously since 1999, and is Russia's longest-serving leader since Joseph Stalin. He is widely expected to win the election as he faces no significant competition and his government has jailed his most serious political rivals, opposition politicians Alexei Navalny and Ilya Yashin.

Putin consistently saw landslide wins in previous elections, but independent observers say the votes were neither free nor far and were rife with fraud.

— Natasha Turak

Russia has destroyed nearly every building in Ukraine's Avdiivka, report says

A new report found that Russian bombings have destroyed nearly every building in the eastern Ukrainian city of Avdiivka.

The Centre for Information Resilience, an independent non-profit group that exposes and tracks human rights abuses and war crimes, detailed in its report the extent to which civilian infrastructure across the city has been flattened. Russian strikes have hit 17 of Avdiivka's educational institutions, nine of its 11 medical clinics, all five of its churches and its three major supermarkets, as well as extensive strikes on residential tower blocks.

"Avdiivka has been a central battleground in Russia's full-scale invasion of Ukraine," Belen Carrasco Rodriguez, who spearheaded the project, wrote in the report.

"The bombardment of the city has been relentless – almost no building in the city centre has been left unscathed, with nearly all critical civilian infrastructure like schools, hospitals and supermarkets largely destroyed or damaged."

— Natasha Turak

Read CNBC's previous live coverage here:

Putin submits candidacy for Russia's 2024 election; EU adopts 12th package of sanctions against Moscow