CNN  — 

Novak Djokovic is being “treated like a prisoner” by Australian authorities, his mother, Dijana Djokovic, told reporters during a press conference in Belgrade, Serbia, on Thursday.

World No. 1 Djokovic is thought to have been transferred to the Park Hotel in Melbourne after having his visa to enter the country blocked ahead of the Australian Open, according to CNN affiliates Seven Network and Nine News.

The hotel, previously used by the Australian government as a Covid-19 quarantine facility, is now being used as an Alternative Place of Detention (APOD) for refugees and asylum seekers.

His mother said that she had spoken briefly with her son on Thursday, adding that he told her he couldn’t sleep.

“I feel terrible since yesterday, the last 24 hours that they are keeping him as a prisoner. It’s just not fair. It’s not human,” said Dijana. She called his current accommodation “terrible,” describing it as “just some small immigration hotel.”

“It’s so dirty and the food is so terrible,” she added. “[The authorities] don’t want to give him any chance to move on to some better hotel or house that he already rented.”

READ: ‘He knew the conditions,’ says Nadal about Novak Djokovic’s ‘rough situation’

The Serbian superstar hasn’t publicly revealed his vaccination status, but in a news conference on Thursday, Australian Prime Minister Scott Morrison said the 34-year-old “didn’t have a valid medical exemption” to the vaccination requirement for arrivals into the country.

According to Our World In Data, 46.76 percent of Serbia’s population has been fully vaccinated against Covid-19.

Djokovic’s legal team sought an urgent injunction against the Australian Border Forces’ decision to revoke his visa. The country’s Federal Court has adjourned the decision until Monday on whether he will be allowed to remain in Australia or be deported, according to Reuters and public broadcaster ABC.

CNN has reached out to lawyers believed to be representing Djokovic and his agent.

“Ultimately, Greg (Hunt), Minister for Health, was absolutely, black-and-white clear to Mr. Djokovic about what his responsibilities and the expectations were,” Deputy Prime Minister Barnaby Joyce told CNN affiliate Seven Network.

Joyce said Djokovic was told to get vaccinated twice to enter the country.

“It’s not good enough just to say that ‘Well, I’ve had Covid.’”

Djokovic tested positive for the virus in June 2020, but since then there have been no reports of him being reinfected.

Djokovic, pictured playing a shot during the Davis Cup in Madrid last month, is hoping to win his 10th title at the Australian Open.

His brother, Djordje, described the action of the Australian authorities as a “serious diplomatic breach,” recounting how communication was abruptly severed between the player and his family.

“In the first 45 minutes I think, he was communicating to the family & team, and that abruptly stopped,” he said during a press conference in Belgrade.

“He had no contact whatsoever as his phone had been taken away from him for three and a half hours.”

Djokovic was eventually given back his phone and taken into another isolation room, his brother added.

After his visa was revoked, Djokovic was taken through Melbourne Airport’s metal detectors and had all his belongings and suitcases taken away from, according to his brother.

“His wallet and change of clothes were taken away from him,” said Djordje. “He was taken to the migrant hotel, to a dirty room and was told that all his belongings will be given back to him on his departure to Europe.”

Serbia’s Foreign Ministry expressed a “verbal protest” to the Australia Ambassador to Serbia, Daniel Emery, the ministry tweeted.

The Ministry called what the tennis player is experiencing in Melbourne an “inappropriate and inhumane treatment.”

Djokovic will be staying in Australia as the injunction goes through the courts, ABC reported.

He is hoping to win his 10th Australian Open title and record-breaking 21st grand slam title this month. The tournament begins on January 17 and concludes on January 30.

CNN’s AnneClaire Stapleton, Philip Wang and Jessie Yeung contributed reporting. Additional reporting from Reuters.