The forceful intervention from Simon puts the tennis chief on a likely collision course with authorities in China, which have so far refused to publicly acknowledge Peng’s allegations. Perceived criticisms of China, which is also due to host the 2022 Winter Olympics in February, have previously resulted in significant public and political backlash, as well as loss of access.

Simon said the WTA had been in conversation with counterparts at the Chinese Tennis Association, who had provided assurances Peng was unharmed in Beijing. However, attempts to reach Peng directly had proved unsuccessful.

“We have reached out to her on every phone number and email address and other forms of contact,” he said. “There’s so many digital approaches to contact people these days that we have, and to date we still have not been able to get a response.”

The alleged email was released only on English-language platforms and domestic Chinese media have not reported on its contents, despite Peng being a household name in China.

When asked about the email, Simon questioned its veracity, describing it as a “staged statement of some type,” noting he had yet to receive a follow up reply, despite responding immediately.

“Whether she was coerced into writing it, someone wrote it for her, we don’t know,” said Simon. “But at this point I don’t think there’s any validity in it and we won’t be comfortable until we have a chance to speak with her,” he added.

Tennis’ popularity in China has grown rapidly over the past few decades, with several Chinese players breaking into the global rankings. The women’s game, in particular, is a big market, thanks in part to the success of Chinese tennis star Li Na, who in 2011 became Asia’s first grand slam singles tennis champion when she won the French Open, followed by a second major title at the 2014 Australian Open.

In recent years, the WTA has made a big push into China. In 2019, the WTA Finals relocated from Singapore to the southern Chinese city of Shenzhen, entering into a lengthy ten year deal.

“When you factor in the commitment to prize money and the commitments to the WTA, and you factor in the stadium build and real-estate elements, it’s over a $1 billion dollar commitment they have made to the WTA Finals and the WTA,” Simon was quoted as saying.

Tennis superstar Naomi Osaka on Tuesday said she was “in shock of the current situation.”

The international concern for Peng, who is a three-time Olympian, having represented China at the 2016 Summer Olympics in Rio, London in 2012, and Beijing in 2008, could now strengthen those calls.

The International Olympic Committee (IOC) said it would not comment on the matter and suggested “quiet diplomacy” should be approached, Reuters reported.

“Experience shows that quiet diplomacy offers the best opportunity to find a solution for questions of such nature,” an IOC spokesperson said on Thursday according to Reuters. “This explains why the IOC will not comment any further at this stage.”

CNN has reached out to the IOC for comment.

Human Rights Watch accused the IOC of being “silent on the Olympian’s disappearance.” In a statement, the global rights group said it is “astonishing that the IOC would accept the government’s assurances, particularly at the expense of a female Olympian making grave allegations.”

Speaking at a press conference Thursday, Chinese Foreign Ministry spokesperson Zhao Lijian said Peng’s accusation is not a diplomatic issue and declined to comment further.