New Delhi, Nov 20 : The US says it is "deeply concerned" about Chinese tennis star Peng Shuai, who has not been heard from since making sexual assault allegations against a top Communist Party official, BBC reported. The White House urged China to "provide independent, verifiable proof" of Peng's whereabouts and safety, the report said. The 35-year-old doubles Grand Slam winner accused China's ex-vice-premier of sexual assault two weeks ago. The Women's Tennis Association has threatened to pull events out of China. WTA Chairman Steve Simon told the BBC that there will be no competitions in China next year without proof that Peng was safe. "We cannot stand by compromises. This is a right and wrong issue," he said, the report said. The WTA has been told Peng is safe, and in Beijing, by the Chinese Tennis Association, although Simon said there has been no confirmation that is true. In a separate development on Friday, three photos of Peng were posted on a WeChat account under her name with the caption "Happy Weekend". However, the authenticity of the post on the Chinese instant messaging service was questioned, BBC reported. Earlier this week, Chinese state media released an email attributed to Ms Peng, but Simon cast doubt about its authenticity. The former number one-ranked doubles player has not been seen in public since posting an allegation about former Vice-Premier Zhang Gaoli on Chinese social media site Weibo on 2 November. She alleged she was "forced" into sexual relations with Mr Zhang -- who served as the country's vice-premier between 2013 and 2018, the report said. /IANS