Chinese authorities lifted a month-long lockdown on the northern city of Xi'an and its 13 million residents as infections subside before the Winter Olympics in Beijing in less than two weeks.
Meanwhile, the two million residents of one Beijing district have been ordered to undergo testing following a series of cases in the capital.
The government told people in areas of Beijing deemed at high risk for infection not to leave the city after 25 cases were found in the Fengtai district and 14 elsewhere.
Fengtai residents have lined up on snow-covered sidewalks in freezing weather for testing.
The Olympics are being held under strict controls that are meant to isolate athletes, staff, reporters and officials from residents.
Athletes are required to be vaccinated or undergo a quarantine after arriving in China.
The announcement by Xi'an's government on Monday followed the restart of commercial flights from the city the day before.
The major industrial centre and former imperial capital, famed as the home of the Terracotta Warrior statue army, had struggled to keep residents fed and the local economy alive while people were confined to their homes.
Xi'an has been a cornerstone of the ruling Communist Party's "zero tolerance" strategy toward COVID-19 that mandates lockdowns, travel restrictions and mass testing whenever a case is discovered.
Xi'an is about 1000 kilometres southwest of Beijing, where the Olympics open February 4.
Access to Xi'an was suspended on December 22 following an outbreak attributed to the Delta variant.
China on Monday reported 18 new local cases, including six in Beijing. The country has 2754 current cases and has reported a total of 105,660, with 4636 deaths.
Despite falling case numbers, pandemic controls have been stepped up before the Olympics, where all participants must be tested before and after their arrival in Beijing.
Organizers on Monday said 39 people among the 2586 athletes, team officials and others who arrived after January 4 had tested positive for the virus upon landing at Beijing airport.
Another 33 people who had already entered the bubble isolating participants from the general public later tested positive, the organising committee said on its website.
The statement said the positives were "outside stakeholders", a term that excludes athletes or coaches.
Australian Associated Press