Tennis star Novak Djokovic has had his visa to enter Australia dramatically revoked on his arrival in Melbourne.
The world number one was held in the city's airport for several hours before border forces announced he had not met entry rules and would be deported, reports BBC.
He has reportedly now been taken to a government detention hotel pending his departure on an outbound flight.
The developments come amid a backlash over a vaccine exemption Djokovic said he got to play in the Australian Open.
Djokovic has not spoken about his vaccination status, but last year he said he was "opposed to vaccination".
Tennis Australia confirmed a medical exemption had been granted for the player "following a rigorous review process involving two separate independent panels" but problems emerged after Djokovic arrived in Melbourne late on Wednesday from Dubai.
In a statement, the Australian Border Force said Djokovic "failed to provide appropriate evidence to meet the entry requirements to Australia, and his visa has been subsequently cancelled.
"Non-citizens who do not hold a valid visa on entry or who have had their visa cancelled will be detained and removed from Australia," it added.
Victoria's acting sports minister tweeted that the state had declined to support his visa application amid the confusion.
Australia's Prime Minister Scott Morrison has denied Djokovic is being singled out and said no one was above the country's rules. At a press conference on Thursday, Mr Morrison said he had been advised that a medical exemption was not in place for the player's entry and said the evidence provided was "found to be insufficient".
Local reports suggest Djokovic could pursue a legal appeal or apply for a new visa so he can re-enter and play in the tournament.
Reuters reports he was later taken from the airport to a hotel in the Melbourne suburb of Carlton which is used for immigration detention. The facility has been the site of Covid-19 outbreaks and a recent fire, according to local media.
Australian Health Minister Greg Hunt earlier described Djokovic's treatment as "tough" but "fair" and said "it's one rule for all under this Australian government".
But the tennis star's treatment has provoked outrage in his native Serbia. His father, Srdjan Djokovic said his son had been held in a room guarded by police at the airport.
"This is not just a fight for Novak, but a fight for the whole world," he said in a statement released to the media.
President Aleksander Vucic said the star was a victim of "harassment" and said that "the whole of Serbia" supported him.
Australia is seeing tens of thousands of Covid-19 cases for the first time after enduring some of the world's strictest restrictions. More than 90% of Australia's over-16 population is fully vaccinated, but some people still cannot travel interstate or globally because of current measures.
Many Australians had previously accused the government of allowing the rich and famous to do as they please while ordinary people remained separated from sick and dying loved ones.
The Australian Open begins on 17 January in Melbourne. Djokovic has previously won the tournament nine times.