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.

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 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."

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".