BEIJING, China (AFP)— Three athletes attending training events for the Beijing Winter Olympics have tested positive for COVID-19, Chinese officials said Thursday, with the country on high alert against the coronavirus ahead of the Games.

Beijing 2022 organisers have left nothing to chance with the games set to start in February, restricting entry to the capital and insisting on daily virus tests for thousands of athletes who will be kept within a “closed-loop” bubble.

One of the athletes, a foreign luger, tested positive at the airport when entering the country and was sent to a quarantine hotel along with another infected teammate as they had no symptoms, officials said last week.

But a third person has now tested positive — another luger and a close contact of the earlier cases, Zhao Weidong, an Olympics organising committee member, said on Thursday.

The latest patient is asymptomatic and has also been transferred to a quarantine facility for “medical observation,” Zhao said at a press conference.

Authorities are continuing to “test people, materials and the environment, as well as conducting health monitoring and disinfecting the environment,” Zhao added.

China is gearing up to tackle one of the largest challenges to its zero-COVID strategy as thousands of athletes are expected to descend on Beijing for the games, which will be held from February 4 to 20.

City authorities this week imposed strict new rules on inbound travellers, requiring all visitors to Beijing to show a negative COVID test result from the past 48 hours and cancelling flights from higher risk areas within the country.

China has kept its domestic case numbers far lower than in most countries, through mass testing, aggressive lockdowns and border controls that left some families separated and many unable to return to work from outside the country.

The Olympics will test the country’s ability to ward off the pandemic, with organisers promising nearly empty stadiums and banning spectators from outside China.

All participating athletes and venue staff must be vaccinated, while tens of thousands of workers in higher-risk industries across the city are being tested multiple times a week.

The Beijing Winter Games organisers have said the coronavirus is the biggest challenge in the lead-up.

The event is also facing boycott calls from international campaigners over human rights concerns in China’s Xinjiang region as well as in Hong Kong and Tibet.