NBA player Enes Kanter Freedom has urged athletes to boycott the Winter Olympics in China.
Three weeks before the opening ceremony in Beijing, the Boston Celtics player said athletes should choose "morals over money".
In an interview with Dan Roan on the BBC's The Sports Desk podcast, Kanter Freedom criticised China's human rights record.
"While we are talking right now there is a genocide happening," he said.
"It is important that athletes use their platform to be the voice for all the innocent people all over the world who don't have a voice.
"There are so many athletes, actors, singers and rappers, or people who have platforms, scared to say a word because obviously there's so much business involved, so much money involved, and sometimes obviously China is paying the bills so they are scared to say a word."
Last year the UK government declared for the first time that genocide is taking place against Uyghurs and others in north-west China. The Chinese government denies all accusations of human rights abuses in Xinjiang.
Switzerland-born, Turkey-raised Kanter Freedom - who changed his name to Freedom after gaining US citizenship - has repeatedly spoken out on China's Tibet policy, the incarceration of its Uyghur Muslim minority and other issues. He told the Sports Desk that he is speaking directly with Olympians.
"I have sat down with many other athletes and had a conversation with them. The first topic I always tell them is: 'Look what they did to their own tennis player Peng Shuai. Are we really going to trust them with our own players?'"
Concerns were raised around Peng's safety and wellbeing last year after the former Wimbledon women's doubles champion retracted claims of sexual coercion she had made against China's former Vice-Premier Zhang Gaoli and retreated from public life.
"I feel like all the athletes out there need to go out and say 'I cannot play a game where there is a genocide happening, where there is all the human rights abuses, where there is people getting tortured and raped in concentration camps'," said Kanter Freedom.
"I'm still hopeful because when I talk to these Olympic athletes I was like, all the gold medals in the world that you can win is not more important than your morals, your principles and your values, so I feel like we need to stand up for the right thing."
The Celtics centre recently appeared in shoes with the message "Free Tibet" written on them.
China has long been accused of suppressing cultural and religious freedom in Tibet, a remote and mainly Buddhist region. The government denies the accusations and says Tibet has developed considerably under its rule.
"You see so many different people like Tibetans, Hong Kongers, Taiwanese people, Uyghurs, Mongolians are suffering," he said. "So I cannot just think about all the business involvements, or remain silent so I had to say something."
Kanter Freedom had his name blocked on China's main social media platform Weibo after calling Chinese President Xi Jinping a "brutal dictator". Boston Celtics games have also been banned from streaming sites in China.
He also criticised the International Olympic Committee (IOC) for holding the Winter Games in China.
"They are part of the problem because China don't respect human rights, friendship or freedom of expression," he said. "Shame on the IOC, organising Olympic Games in a country like China."
While the UK, US, Canada and Australia have announced diplomatic boycotts of the Winter Olympics, which run from 4-20 February and are followed on 4-13 March by the Winter Paralympics, the IOC has stated that it takes a politically neutral stance, and that it sees the Games as an apolitical sporting event.
Kanter Freedom moved from Turkey to the United States aged 17 and later became the third overall draft pick for Utah Jazz in the 2011 NBA draft.
The 29-year-old is a longstanding critic of Turkish President Recep Tayyip Erdogan, and the Turkish authorities cancelled his passport and issued an international warrant for his arrest in 2019, when they accused him of having links to the organisers of a failed coup in 2016. Kanter Freedom's father was incarcerated in Turkey in the fallout from the attempted coup, but has since been acquitted of terrorism charges and released.
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