China tells Winter Olympic spectators to clap, not cheer, for athletes, and Xi’an, a major city, locks down.

ZHANGJIAKOU, China — Spectators on the Winter Olympics subsequent February ought to clap however not shout in help of athletes. Waiters, cleaners and different help workers will not be allowed to depart Olympic venues to go to their households. And any Olympic members leaving the neighborhood for the remainder of China might be required to spend a minimum of one week in quarantine, adopted by a minimum of two weeks of isolation at dwelling.

As the Omicron variant spreads quickly across the globe, China is taking elaborate precautions to stop the coronavirus from reaching its personal inhabitants or members within the Winter Games. Chinese officers are additionally bracing the general public for the inevitability that some infections will emerge on the Olympics, the place everybody will face every day P.C.R. exams.

“A certain number of positive cases will become a high probability event,” Han Zirong, the secretary common of Beijing’s Winter Games organizing committee, instructed reporters on Thursday.

China has barred abroad spectators from getting into the nation. It is permitting vaccinated international athletes, trainers, coaches, referees, journalists and a few others to enter with out enduring the same old two or extra weeks of quarantine adopted by a week of dwelling confinement.

The exemption, nevertheless, comes with a stringent requirement that foreigners not depart a “closed loop” of inns and sports activities venues, linked by particular buses and trains.

“We must never go outside the closed loop, let alone reach the city level — this is our bottom line,” mentioned Huang Chun, deputy director of the Olympic organizing committee’s Office of Epidemic Prevention and Control.

China has reported dozens of coronavirus instances every day this week. On Thursday, the native authorities locked down Xi’an, a metropolis of 13 million individuals. At least 242 instances have occurred there in an outbreak this month. Beijing has not divulged what number of contain the Omicron variant.

The nation has been largely profitable in controlling the virus by quarantining a whole lot of shut contacts of contaminated individuals, and in some instances contacts of contacts. But equally broad measures on the Olympics may make it laborious to maintain the Games.

Some precautions are already seen at a ski resort within the mountains close to Zhangjiakou, about 100 miles northwest of Beijing, the place almost half of the Olympic occasions might be held. Thick, clear plastic sheeting from ground to ceiling separates bus drivers from their passengers.

At the resort’s high-speed-rail station, guests should present proof of a detrimental P.C.R. take a look at within the previous 48 hours. Also required is proof on a smartphone app that the traveler has not visited any Chinese metropolis within the earlier two weeks that has had a latest an infection.

For building employees placing the ending touches on the venues, the authorities already do nucleic acid exams as soon as each three days, Jia Maoting, the final supervisor of the Olympic Sports Construction and Development Company, instructed reporters throughout a go to to the Olympic ski leap venue.

Mr. Han, the secretary common of the Olympic organizing committee, cautioned that additional measures could also be added within the weeks to come. “Everything depends on the changes in the global and Chinese epidemic situation,” he mentioned, “especially the infectiousness of the new mutant strain, Omicron.”

Liu Yi and Li You contributed analysis.