Serbian tennis star Novak Djokovic left a political message on a TV camera lens at the French Open on Monday in response to violent clashes in Kosovo.

Following his first-round victory against American Aleksandar Kovacevic, Djokovic wrote "Kosovo is the [heart] of Serbia. Stop the violence" in Serbian on a camera lens, using a heart symbol.

The message was displayed on the big screen of Court Philippe Chatrier.

Tensions have been rising in the past week in Kosovo, which declared independence from Serbia in 2008. There were clashes with protestors on Monday after ethnically Albanian mayors took office in northern Kosovo, a majority Kosovo Serb area, following April elections that Kosovo Serbs had boycotted.

At least 34 soldiers with NATO's peacekeeping mission in Kosovo were injured during the clashes.

Djokovic elaborated on his message in Serbian at a press conference, saying: "This is the least I could have done. I feel the responsibility as a public figure -- doesn't matter in which field -- to give support.

"Especially as a son of a man born in Kosovo, I feel the need to give my support to our people and to the entirety of Serbia. I don't know, and I think many others don't know, what the future brings for Kosovo and for Serbian people, but it's necessary to show support and demonstrate unity in these kinds of situations. I don't know what will happen."

Djokovic's reference to the "entirety of Serbia" reflects the policy of the Serbian government, which still considers Kosovo to be an integral part of its territory and has not recognized the country's independence.

NATO's Kosovo Force (KFOR) said that recent developments in Kosovo had prompted it to increase its presence in the northern part of the country on Monday.

According to the Italian defense ministry, some KFOR soldiers were injured when protesters threw "Molotov cocktails with nails, firecrackers and stones."

Reuters reported that Djokovic said he had not been approached by French Open organizers about the message he wrote on the camera lens, a photo of which he also shared on Instagram. CNN has contacted the French Tennis Federation for comment.

"My stance is clear: I am against wars, violence and any kind of conflict, as I've always stated publicly. I empathize with all people, but the situation with Kosovo is a precedent in international law," the 36-year-old added.

As a child growing up in Belgrade, Djokovic lived through NATO's 78-day bombing campaign in 1999, which was intended to end atrocities committed by troops of Yugoslavia's then-president Slobodan Milošević against ethnic Albanians in Kosovo.

Djokovic is aiming to win his 23rd grand slam title at the French Open, which would move him clear of Rafael Nadal at the top of the men's all-time list.