A video claiming to show Chinese player Peng Shuai out with friends is “insufficient” evidence of her safety, says Women’s Tennis Association chief Steve Simon.

“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 Simon.

Simon has written to the Chinese Ambassador to the United States, Qin Gang, asking him to discuss the “urgent issue” with high-ranking Chinese government officials “so it can be successfully resolved”.

The WTA chairman also requested for Peng to be allowed to leave China or speak directly to him in a live video call with nobody else present.

Peng, 35, has not been in direct contact with the WTA since making sexual assault allegations against a former China vice-premier two weeks ago.

The UK government said it was following the case closely and remained “extremely concerned”.

“The Chinese authorities should urgently provide verifiable evidence of her safety and whereabouts,” said a spokesperson for the Foreign, Commonwealth and Development Office.

“Everyone should be allowed to speak out without fear of repercussions. All reports of sexual assault, anywhere in the world, should be investigated.”

The governing body of the women’s professional tour has been told Peng is safe, and in Beijing, by the Chinese Tennis Association, although Simon said on Friday there has been no confirmation if that is true.

On Saturday, the editor of the Global Times – which is a Chinese state-affiliated media organisation – posted the clips of Peng which he said were filmed this weekend.

“The video content clearly shows they are shot on Saturday, Beijing time,” said Hu Xijin.

However, the authenticity of the videos was questioned by BBC China media analyst Kerry Allen.

She said it appeared a date had been blurred out of the video.

“I am glad to see the videos released by China state-run media that appear to show Peng Shuai at a restaurant in Beijing,” added Simon.

“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.”

Federer adds voice to Peng concerns

Peng is a former world number one doubles player who has won two Grand Slam titles – at Wimbledon in 2013 and the 2014 French Open, both alongside Chinese Taipei’s Hsieh Su-wei.

She also achieved a career-high singles rankings of 14 in 2011 and reached the US Open singles semi-finals in 2014.

Fears for Peng’s safety have continued to grow since she said on 3 November she was “forced” into a sexual relationship with former China vice-premier Zhang Gaoli.

Peng made the allegations in a post on Chinese social media site Weibo and they were soon deleted from China’s internet.

It is the first time such a claim has been made against one of China’s senior political leaders.

Swiss star Roger Federer has added his voice to concerns about Peng’s welfare, joining Serena Williams, Novak Djokovic and many other top players in speaking out about the situation.

“I hope she is safe, the tennis world is united for her,” said 20-time Grand Slam champion Federer.

“I hope good news will come from her soon.”

People across tennis – including other past and present players, coaches and journalists – have been demanding answers about Peng’s whereabouts, as have other high-profile sports stars, actors and politicians.

Many have been using #WhereIsPengShuai on Twitter posts, along with a photo of her.

Wimbledon said it had been “working in support of the WTA’s efforts” to establish her safety and was “united with the rest of tennis in the need to understand that Peng Shuai is safe”.