The Beijing 2022 Winter Olympics is facing "great pressure," the organizers said Monday, as they try to ensure the safety of athletes and to determine whether domestic fans can attend the Winter Olympics amid the ongoing COVID-19 pandemic.

February's Games could be the most restricted mass sporting event since the pandemic began, with no international spectators allowed and a vaccine mandate for anyone entering a strictly enforced "bubble."

"If conditions allow we will arrange for spectators to attend certain competitions," Yao Hui, director of Beijing 2022's Venue Management Department, told a news conference, referring to test events starting this week at the National Speed Skating Oval and at eight different Olympic venues before the end of the year.

The presence of over 2,000 international participants presents a "massive test" for organizers, said Huang Chun, deputy director of Beijing 2022's COVID-19 Prevention and Control Office.

"This will undoubtedly and clearly increase the risk of the import and spread of COVID-19," Huang said, according to Reuters.

Foreigners taking part in the test events must have had a COVID-19 vaccine and on arrival in China must stick to rules such as limiting their movements to competition and training venues.

"We face great pressure in epidemic prevention and control," Huang said.

China has virtually sealed off its borders to keep COVID-19 infections out. But ahead of the test events, it allowed entry to participants that are mainly from Asia, as well as Europe and North America.

Organizers said they will ensure that test events are carried out using the same arrangements as the Winter Olympics.

Unlike the Tokyo Olympics, the Beijing Games will have spectators, albeit only people living in mainland China.

But the Winter Olympics bubble will be much stricter than it was in the Japanese capital.

Only fully vaccinated participants, including media and venue staff, can enter the "closed-loop management" bubble without a 21-day quarantine. They cannot leave the bubble for the duration of the Games.

"From when they enter the bubble to when they leave China, we will strictly enforce full-course point-to-point closed-loop management policies," Huang was quoted as saying by Agence France-Presse (AFP).

"In the closed loop, all event participants can only move between the competition venues and participate in activities related to their work, competition, and training. Other activities are not allowed."

The Beijing Olympics, which is facing calls for a boycott from rights groups, is scheduled for Feb. 4-20.

Test events in certain sports were scheduled for last winter but were canceled due to the pandemic.

China, where the coronavirus emerged toward the end of 2019, has wrestled down the number of local infections to a trickle by deploying aggressive, mass testing and keeping its borders extremely tight.