Serbian authorities have threatened to arrest Luka Jovic should he break his self-quarantine.

The 22-year-old came under criticism for flying from Spain to Serbia on Thursday.

Real Madrid doctors told Jovic that he could continue his self-isolation in Serbia, but he has been seen out in Belgrade.

"While in Spain, I tested negative for coronavirus, and I decided to travel to Serbia to help and support our people and be close to my family, in agreement with my club," wrote Jovic on Instagram.

"When I landed in Serbia, I again tested negative for coronavirus. I am very sorry that some people did their job unprofessionally and did not give me the correct instructions on how to behave in self-isolation."