Unverified photos of tennis player Peng Shuai posted online

Unverified photos of Peng Shuai have been posted online by a state-affiliated journalist as international concern mounts for the Chinese tennis star not seen publicly since accusing a former vice-premier of forcing her to have sex.

The Twitter account @shen_shiwei, labelled "Chinese state-affiliated media" by the social network, posted four undated images of her late Friday.

In a tweet, @shen_shiwei said the pictures, which could not be independently verified by AFP, were shared on Peng's WeChat Moments, a function often restricted to friends, to wish her followers a "good weekend".

One photo shows the smiling player with a cat in her arms, with stuffed animals, a trophy, a Chinese flag and certificates visible in the background.

Another shot shows a selfie of Peng with a toy from the children's animation Kung Fu Panda, with an image of Winnie the Pooh in the background.

The children's character is often censored online in China as critics say Chinese leader Xi Jinping resembles the cartoon.

Requests for comment from the user @shen_shiwei were not immediately answered.

Twitter is blocked in China and only people with a VPN-type workaround can access it. However, many Chinese diplomats and official state media have accounts to defend China's point of view.

Earlier this month, the former Wimbledon doubles champion alleged on Chinese social media site Weibo that Communist Party grandee Zhang Gaoli, now in his 70s, had forced her into sex during a long-term on-off relationship.

Her message was quickly scrubbed from the Chinese web, and Beijing has repeatedly refused to comment on the case.

The United States on Friday demanded proof of the 35-year-old's whereabouts and well-being, with the United Nations also calling for a fully transparent investigation into Peng's claims.