An outcry over the whereabouts of Chinese tennis star Peng Shuai escalated on Friday as the Women's Tennis Association (WTA) said it was prepared to pull its tournaments out of China if they were not satisfied with the response to her sexual assault allegation.

Former doubles world number one Peng has not been seen or heard from publicly since she said on Chinese social media on Nov. 2 that the former vice-premier, Zhang Gaoli, coerced her into sex and that they later had an on-off consensual relationship.

Neither Zhang or the Chinese government have commented on her allegation. Peng's social media post was quickly deleted and the topic has been blocked from discussion on China's heavily censored internet.