The Women's Tennis Association has announced the immediate suspension of all tournaments in China amid concern for Chinese tennis player Peng Shuai.
Peng, 35, disappeared from public view for three weeks after accusing a top Chinese official of sexual assault. WTA chief Steve Simon said that he had serious doubts that Peng was free, safe and not subject to intimidation.
"In good conscience, I don't see how I can ask our athletes to compete there," he said. In response, China said it opposes the politicisation of sports.
News of the WTA suspending tournaments in China has been removed from the internet in the country, although the WTA's account on Chinese social media site Weibo is still available. The WTA has repeatedly called for a full investigation into Peng's claims.
There was widespread concern for Peng after she accused former Vice-Premier Zhang Gaoli of sexual assault. She said that she was safe and well during a video call with Thomas Bach, the president of the International Olympic Committee, in November.
However, the WTA said the video was insufficient evidence of Peng's safety. In a lengthy statement, Simon said that he was greatly concerned about the risks players and staff could face if events were held in China in 2022.
"The leadership in China has not addressed this very serious issue in any credible way," he said. "If powerful people can suppress the voices of women and sweep allegations of sexual assault under the rug, then the basis on which the WTA was founded - equality for women - would suffer an immense setback.
"I will not and cannot let that happen to the WTA and its players." The suspension also includes tournaments in Hong Kong.
World No.1 Novak Djokovic backed the WTA's move and said Peng's health was of the utmost importance to the world of tennis. He said: "I support fully the WTA's stance because we don't have enough information about Peng Shuai and her well-being."
Former world number one and WTA founder Billie Jean King praised the organisation for taking a strong stand. "This is another reason why women's tennis is the leader in women's sports," she wrote on Twitter.
"The WTA is on the right side of history in supporting our players." A number of players, including two-time Wimbledon champion Petra Kvitova and US Open quarter-finalist Shelby Rogers, tweeted their support for the WTA's decision.
Julian Knight MP, who chairs the Digital, Culture, Media and Sport Committee, said he welcomed the stance, adding: "If only other sports showed this solidarity and moral clarity." There have been no WTA events in China for the past two years because of the coronavirus pandemic.
However, the governing body has heavily relied on Chinese investment in its tour in recent years, leading to a number of lucrative tournaments being held in the country. China hosted nine tournaments in the 2019 season, including the season-ending WTA Finals, with a total of $30.4m (£22.6m) in prize money.
Simon said that he was worried about the financial implications of not playing in China, but that Peng's case is bigger than the business. He said: "This is something that we simply cannot walk away from.
"If we walk away from what we have requested, what we are telling the world is [that] not addressing sexual assault with the respect and seriousness that it requires is OK, and it is just not. It is just something that we cannot let happen and we cannot walk away from that."
Peng, a former world No.1 in doubles, wrote on Chinese social media site Weibo that she was forced into a sexual relationship with Zhang. The post was taken down minutes later and Peng was not seen in public for some time.
A number of tennis players have used the hashtag #WhereisPengShuai on Twitter to draw attention to the issue. Simon said that he would not ask the ATP to make a similar stance in the men's game, but added that the governing body was supportive of their stance.
"I do not think the ATP not suspending tournaments undermines our position," he said.
"Our position is about what is best for the WTA and women's athletes and we are going to stick with that position. Others will make the decisions they think are appropriate to them."
He added that he remained hopeful that the Chinese authorities would take steps to "legitimately address" Peng's claims. Simon added: "I very much regret it has come to this point but China's leaders have left the WTA with no choice.
"Unless China takes the steps we have asked for, we cannot put our players and staff at risk by holding events in China." China issued a statement on October, stating that people should stop deliberately and maliciously hyping the issue up, let alone politicise this issue".
Zhang Gaoli, who retired from his government role in 2018, has yet to address the claims maid. The 2022 Winter Olympics and Paralympics are set to be held in Beijing in February and March.