PARIS (AP) — French Sports minister Amelie Oudea-Castera said Wednesday that Novak Djokovic's political message about Kosovo was “not appropriate” and warned the former top-ranked Serb player that he should not do it again.

Speaking on TV station France 2, Oudea-Castera said French Open director Amelie Mauresmo spoke with Djokovic and his entourage to insist on the principle of “neutrality" on the field of play.

“When it comes to defending human rights and bringing people together around universal values, a sportsperson is free to do so,” she said. But Oudea-Castera added that Djokovic's message was “militant, very political” and “must not be repeated.”

Djokovic has drawn criticism from Kosovo’s tennis federation after offering his thoughts on clashes in northern Kosovo between ethnic Serbs and police and NATO peacekeepers.

After a first-round victory in Paris on Monday, Djokovic wrote in Serbian on the lens of a courtside TV camera: “Kosovo is the heart of Serbia. Stop the violence.”

Kosovo’s tennis federation said Tuesday that Djokovic’s comments were “deplorable” because he was stoking tensions between Serbia and Kosovo.

The International Tennis Federation has not opened a disciplinary case.

“We received a letter from Kosovo which we have answered," said ITF president David Haggerty. "But essentially we have forwarded their letter to the French federation, to the French Open, it’s their tournament, and to the ATP who have the rules — the two of them together have the rules and regulations for the event.”

Haggerty added that “athletes have to be careful on their political views. Sports and politics is what we have been talking about and we really want to keep them separate.”

A former province of Serbia, Kosovo’s 2008 declaration of independence is not recognized by Belgrade. Ethnic Albanians make up most of the population, but Kosovo has a restive Serb minority in the north of the country bordering Serbia.

Djokovic, who has won 22 Grand Slam titles, is scheduled to play in the second round at Roland Garros on Wednesday.

Speaking to reporters in Serbian, Djokovic said Monday that he thought what he wrote on the TV camera was “the least I could do. I feel responsibility as a public figure ... as well as a son of a man who was born in Kosovo.”

Without mentioning Djokovic by name, French Open organizers indicated in a statement issued Tuesday that no rules had been broken, saying: “Occasionally, discussions about international news events enter the realm of the tournament, which is understandable.”

Ukrainian player Elina Svitolina was asked about the issue Wednesday after her second-round victory. She has spoken out about Russia's invasion of her country, and said athletes should be able to express opinions.

“Well, we are living in the free world, so why not to say your opinion on something? I feel like if you stand for something, you think that this is the way, you should say (it),” said Svitolina, who also acknowledged, “I don’t know the politics of Serbia.”