French Sports Minister Amelie O'Dea-Castera has condemned Serbian Novak Djokovic's letter after his first-round match at Roland Garros, the second Grand Slam, calling Kosovo "the heart of Serbia".

In response to a question by France 2, the minister and former director of the French Tennis Federation indicated that the message of the world number three was "inappropriate" and that "this should not start again", classifying it as "hardline" and "very political".

The minister, who was invited to comment on the expression of political positions during the French championship, such as those of Ukrainian athletes since the Russian invasion of their country, said she would not categorize "the two topics at the same level".

"What is happening to Ukrainians inside the stadiums is very painful and very difficult," she said.

Djokovic, who was born in the Serbian capital Belgrade, sparked controversy on Monday when he wrote in Serbian the letter: "Kosovo is the heart of Serbia. Stop the violence" on camera, after his first-round victory over American Aleksandar Kovačevic.

NATO-led peacekeepers on Monday dispersed Serb protesters who again clashed with police in northern Kosovo to demand the dismissal of newly elected Albanian mayors, as ethnic tensions rise in the Balkan country.

"Kosovo is the heart of Serbia – stop the violence", Novak Djokovic wrote on camera after winning the first round of Roland Garros

— Spriter (@Spriter99880) May 29, 2023

Djokovic, 36, told Serbian media at the tournament: "Kosovo is our cradle, our stronghold and the centre of the most important things for our country. There are many reasons to write that on camera."

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Djokovic, who has won 22 major titles, added: "I'm not a politician and I have no intention of engaging in political discussions, it's a very sensitive subject. Of course it hurts me a lot as a Serb to see what is happening in Kosovo and the way our people have been evicted from municipal offices, so that's the least I can do."

Weeks ago, Amelie O'Dea-Casterra called for players to be punished for refusing to take part in a gay support event.

This came against the backdrop of a number of players refraining from participating in an event to support gays, and refusing to wear shirts with rainbow numbers.

French media revealed that most of the players are from African countries.

French newspaper Le Parisien quoted the sports minister as saying, "What happened I deeply regret. We live in a country that has always encouraged respect for human rights."

"In my opinion, clubs should have a dialogue with their players. Action must be taken against these players."