International tennis chiefs insisted on Wednesday that “political statements” are not banned at Grand Slam events after Novak Djokovic controversially wrote “Kosovo is the heart of Serbia” on a camera at the French Open.

Djokovic defended his message in comments to Serb media, saying that Kosovo is Serbia’s “cradle, our stronghold”. The International Tennis Federation (ITF), the governing body of the sport, said they had received a request from the Kosovo Tennis Federation demanding Djokovic be sanctioned over his actions.