Djokovic is currently being held in an immigration detention centre in Australia after arriving in the country without proof of vaccination.

He is now fighting deportation from the country days before the start of the Australian Open which he hopes to compete in later this month.

The 34-year-old Serbian, an outspoken critic of mass vaccination, said in his court application he had a valid visa and medical exemption from the organiser of the tournament because he tested positive for coronavirus on 16 December last year.

Gluten-free food deliveries, exercise equipment and a SIM card to contact family - the conditions in tennis star's immigration detention

However, a press release from the Tennis Association of Serbia appears to show Djokovic meeting with young tennis players the next day.

It is unclear if Djokovic knew if he had COVID when the pictures were taken.

The photographs are from an awards ceremony which took place at the Novak Tennis Center in the Serbian capital Belgrade.

Djokovic can be seen standing with young people who are holding up their trophies.

Another shows the defending Australian Open winner standing at the back of a group shot.

Tennis Australia has 'not knowingly misled players'

Sky News has not been able to confirm when the event took place, but the Tennis Association of Serbia shared the images on 17 December and referred to the ceremony as taking place "today".

The press release states that the event was held "without a wider audience because of epidemiological measures due to the coronavirus pandemic".

The date Djokovic said he tested positive for coronavirus - 16 December - was the same day he was presented with a stamp by the Serbian national postal service at the PTT Museum in the capital Belgrade. He tweeted about the presentation the following day.

Members of Djokovic's family and supporters of the tennis star who are opposed to his detention in Australia have taken part in protest action in Belgrade.

Srdjan Djokovic, the six-time Wimbledon champion's father, said: "Guys, this has nothing to do with sport, has nothing to do with Novak, this is a political decision, political.

"We are not angry with the people of Australia, we are actually angry with their politicians, with those guys who now keep arguing among themselves as to who is right - the federal government or the local government where (the city of) Melbourne is, or the Tennis Association of Australia, etc. He certainly wouldn't have gone there if they hadn't given him the permit to enter (Australia) and win the 10th grand slam, the Australian Open."

Reports say Tennis Australia told unvaccinated players they may be able to obtain a temporary exemption if they had recovered from COVID in the past six months, according to a leaked letter.

Tennis Australia said it had not knowingly misled players and had always urged players to get vaccinated.

Why is Djokovic being denied entry to Australia - and what are their travel rules?

"We have always been consistent in our communications to players that vaccination is the best course of action - not just as the right thing to do to protect themselves and others, but also as the best course of action to ensure they could arrive in Australia," Tennis Australia said in a statement quoted by local media.

Djokovic was detained after his visa was cancelled on Thursday, hours after he arrived at Melbourne Airport.

Czech player's visa revoked

The tennis player will argue for his visa to be reinstated at a court hearing on Monday.

Djokovic has been given access to gluten-free meal deliveries and exercise equipment during his stay in immigration detention, according to the Serbian prime minister's office.

Serbian officials are "trying everything to make the situation easier for Djokovic", a statement said.

It comes as two other people connected to the Australian Open voluntarily left the country after being told to do so by border officials.

One of them is Czech player Renata Voracova, whose visa was also revoked due to issues with her exemption.