Simon described a video of Peng released by state media in China as "insufficient" and said he remained "concerned" over the former Wimbledon doubles champion’s wellbeing.

Hu Xijin, editor-in-chief of the state-backed Global Times, posted footage showing Peng at a restaurant with her coach and friends in Beijing.

A further video was published by Hu which shows Peng at the Opening Ceremony of a junior tennis tournament in the Chinese capital where she is introduced to the crowd.

Another reporter from the Global Times published a video where Peng is shown signing large tennis balls for children.

Pictures have also been released of Peng at the Fila Kids Junior Tennis Challenger Finals on the tournament’s official WeChat page.

However, the WTA has said the images fail to address its concerns.

"While it is positive to see her, it remains unclear if she is free and able to make decisions and take actions on her own, without coercion or external interference," said Smith when commenting on the video of Peng having dinner.

"This video alone is insufficient.

"As I have stated from the beginning, I remain concerned about Peng Shuai’s health and safety and that the allegation of sexual assault is being censored and swept under the rug.

"I have been clear about what needs to happen and our relationship with China is at a crossroads."

The video at the restaurant shows Peng sitting with a man and two women listing to a conversation.

According to reports, the man claims "tomorrow is November 20th" only for one of the women to interject, saying "it is the 21st".

Peng, a former doubles world number one, who competed in three consecutive Olympic Games at Beijing 2008, London 2012 and Rio 2016, has not been seen or heard from publicly since November 2.

That is when she made allegations against Zhang Gaoli, a former senior vice-premier and high-ranking member of the Chinese Communist Party, on Chinese social media platform Weibo.

Peng claimed Zhang sexually abused her 10 years ago and admitted to an on-off extra-marital affair since the coercive incident.

The social media post was taken down within 20 minutes, but it was not reported in Chinese media, subject to blanket censorship.

Concerns for her safety increased when Chinese state media released a letter purporting to be Peng to Simon.

The head of the WTA said he has "a hard time believing that Peng Shuai actually wrote the email we received or believes what is being attributed to her".

Simon has now threatened to pull out of all 2022 WTA events hosted in China, should independent and undeniable evidence of Peng's whereabouts and well being not be provided.

The International Olympic Committee (IOC) has been criticised for its approach from many other quarters after it said that the best course of action was "quiet diplomacy" and repeated its stance in a statement yesterday.

"The IOC appreciates the concerns expressed by so many athletes and National Olympic Committees," a spokesperson said.

"We also welcome the support of the IOC Athletes’ Commission for our quiet diplomacy approach.

"This approach means we will continue our open dialogue on all levels with the Olympic Movement in China."

Emma Terho, head of the IOC Athletes’ Commission, said it was "very concerned" about Peng’s situation and supported the IOC’s quiet diplomacy approach.

She said she hoped "a way can be found for direct engagement between her and her athlete colleagues".

Richard Pound, the long-serving member of the IOC, doubted Peng’s case would result in the Winter Olympics not taking place in Beijing in February but refused to completely rule out the possibility of it happening.

"If that's not resolved in a sensible way very soon it may spin out of control," said Pound.

"It may [force IOC into taking a harder line].

"Whether that escalates to a cessation of the Olympic Games I doubt it.

"But you never know."

Paris 2024 President Tony Estanguet, a former IOC Athletes' Commission vice-chair and ex-IOC member, has called for the "greatest transparency" regarding the health and safety of Peng.

The Lawn Tennis Association - Britain's tennis governing body - and the National Olympic Committees of The Netherlands and Germany have all shared concern over Peng's safety along with leading tennis players, including Serena Williams of the United States, Naomi Osaka of Japan and Novak Djokovic of Serbia.

US President Joe Biden is also "deeply concerned" with the situation, and wants China to "provide independent, verifiable proof", according to White House press secretary Jen Psaki.

Critics of the regime say China's record on human rights makes it an unfit Olympic host, and the Peng case is likely to give rise to more criticism over how China handles dissent.