A Chinese official told reporters in January that any behaviour against the Olympic spirit, and “especially against Chinese laws and regulations” would be subject to punishment.

Senator Jeff Merkley and Representative James McGovern, both Democrats, cited the remark in a public letter to the US Olympic and Paralympic Committee (USOPC), writing that risks to freedom of expression and data privacy at the Games “demand an urgent effort” to address.

“Chinese authorities have imposed exit bans on US citizens, and even jailed foreign nationals, for political or specious reasons,” said the lawmakers, who lead the US Congressional-Executive Commission on China.

The USOPC should “redouble efforts” to engage with the International Olympic Committee (IOC), fellow national Olympic committees, and the US State Department to ensure that plans and procedures are in place to protect athletes should they be punished for free expression, they said.

“We further request that the USOPC communicate to the public that it is taking such steps,” they said, adding that the committee should be “prepared to defend any Olympians who speak out”.

Rights groups have long criticised the IOC for awarding the Games to China, citing its treatment of Uighurs and other Muslim minority groups, which the US has deemed genocide. China denies allegations of human rights abuses.

Some Western countries, worried about information security, have suggested their delegations not bring their own mobile phones to the Feb 4-20 Olympics.

Researchers have said the Beijing Organising Committee’s MY2022 app, which all attendees must use for Covid-19 monitoring, has flaws that make it vulnerable to privacy breaches.

Several countries, including the US, Britain, and Australia, have announced diplomatic boycotts of the Games over concerns about human rights in China, though their athletes will still compete.