Image source, Getty ImagesImage caption, The email had been allegedly sent from Peng Shuai to WTA head Steve Simon

The head of the Women's Tennis Association (WTA) says he remains concerned about Chinese tennis star Peng Shuai after she accused a top official of sexual assault.

Steve Simon said he would not engage in further email communications because he was not convinced her earlier replies were not "influenced by others".

Ms Peng disappeared from public view for three weeks after accusing the former Vice-Premier Zhang Gaoli.

The WTA has sought proof she is safe.

The UN and US have also demanded information on her whereabouts along with a number of major tennis players including Serena Williams, Naomi Osaka and Novak Djokovic.

Ms Peng, 35, who is one of China's top tennis players, had earlier this month written a 1,600-word post on Chinese social media platform Weibo, where she laid out her allegations against the 75-year-old Mr Zhang.

This is the most significant case of its kind in China's slow-moving #MeToo movement.

  • Peng Shuai: What we know so far
  • How China censored a tennis star

Last Sunday, Peng Shuai said she was safe and well in a video call involving International Olympic Committee President Thomas Bach.

China has reacted angrily to the attention, particularly after the sceptical reaction to the IOC statement on the call – as well as a series of photographs and videos that appeared to show all was well with the athlete.

Some have accused Mr Simon of ignoring Ms Peng's emails.

Image source, IOC / Greg MartinImage caption, IOC President Thomas Bach spoke to Ms Peng for 30 minutes on Sunday

On Saturday, a WTA spokesman told AFP news agency Mr Simon "remains deeply concerned that Peng is not free from censorship or coercion and decided not to re-engage via email until he was satisfied her responses were her own, and not those of her censors.

"The WTA remains concerned about her ability to communicate freely, openly, and directly."

Mr Simon has threatened to pull the WTA's business out of China, which would have a big effect. There are 10 WTA events scheduled to take place in the country next year including the Wuhan Open and WTA finals in Shenzhen.

The Wuhan Open next year will be the first time tennis players have returned to the city since the start of the pandemic.

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To play this video you need to enable JavaScript in your browser.Media caption, WTA chairman: We are worried about Peng's safety