Ukraine's ambassador to Australia on Friday urged tennis officials to ban Novak Djokovic's father from the Australian Open after he was filmed posing with fans holding Russian flags.
"He should be stripped of his accreditation," Ambassador Vasyl Myroshnychenko told AFP.
Myroshnychenko also called on Djokovic, who is preparing to face Tommy Paul in the semi-finals of the tournament, to personally apologise and to clarify his stance on the Russian invasion of Ukraine.
"He should apologise for what has happened, and condemn the Russian invasion of Ukraine," he demanded.
A video posted to a pro-Russian Australian YouTube account on Thursday showed Djokovic's father Srdjan posing with a man holding a Russian flag with Vladimir Putin's face on it.
The video was captioned: "Novak Djokovic's father makes bold political statement."
Serbian tennis reporters confirmed it was Djokovic's father and the Melbourne Age newspaper reported that he said in Serbian: "Long live Russia."
Another man was photographed by AFP inside the stadium during Djokovic's match with a T-shirt bearing the Russian pro-war "Z" symbol.
Last year, Djokovic was deported from Australia for refusing to be vaccinated against Covid-19, the controversy overshadowing the start of the tournament.
Myroshnychenko said the player's response to the latest controversy would again draw attention away from what was happening on the court.
The last Open was all about Djokovic," he said. "Now it's all about Russian flags and Djokovic as well."
Ukrainian former player Alex Dolgopolov said on Twitter the flag furore was "absolutely disgusting".
Myroshnychenko was instrumental in persuading Australian Open organisers to ban Russian and Belarusian flags from this year's Grand Slam.
- 'Honour and dignity' -
Russia's embassy in Australia had hit back at the ban, calling it "another example of unacceptable politicisation of sports".
Simeon Boikov, who runs the YouTube channel that posted the flag footage, urged Russian supporters to descend on Melbourne Park ahead of Djokovic's quarter-final match against Andrey Rublev.
"This is about honour and dignity now. This is an attack on honour and dignity. This has got nothing to do with the war," he said in a video message.
Australia's conservative opposition leader, Peter Dutton, called the behaviour of Djokovic's father "bizarre".
"The Russian onslaught continues and frankly everybody of goodwill should be trying to deter, not encourage President Putin," he told Australia's Nine Network.
Tournament organiser Tennis Australia said Thursday it would continue to work with security to enforce entry rules, without directly addressing the incident with Djokovic's father.
"Players and their teams have been briefed and reminded of the event policy regarding flags and symbols and to avoid any situation that has the potential to disrupt," it said.
"We continue to work closely with event security and law enforcement agencies."
Since Russia's invasion of Ukraine last year, Russian and Belarusian players have normally competed under a neutral white flag as independents, as is the case at the Australian Open.