BEIJING -- Beijing Municipality has swung into action, adopting swift and targeted measures to contain the spread of infections after a local resurgence in COVID-19 cases was reported recently.

On Sunday, Fengtai, a district of about 2 million people, conducted district-wide nucleic acid testing to mitigate the risk of community transmission after a cluster infection was detected.

Authorities in Fengtai set up over 1,000 sampling sites -- mostly in residential areas -- and dispatched over 13,000 medical and service support workers to ensure smooth and efficient testing. Besides, 10 other districts in the Chinese capital sent 4,600 medical personnel to Fengtai to help with the anti-epidemic work.

"Early in the morning, workers set up the sampling site in our residential compound and started knocking on doors to remind residents to undergo testing," said a woman surnamed Xu in Shouwei residential area on Sunday.

Authorities in other districts of Beijing have encouraged residents to undergo nucleic acid testing to identify potential infections and thwart the spread of the coronavirus.

"I have been tested and it was very fast. I plan to do it again in a few days," said a woman surnamed Zhang in Xicheng district. "Given the latest resurgence, undergoing the testing offers us assurance."

Beijing reported nine locally transmitted COVID-19 cases, including five confirmed cases and four asymptomatic carriers from 4 p.m. Saturday to 4 pm Sunday.

Since Jan 15, the city has reported a total of 43 local COVID-19 cases, with six attributable to the Omicron variant and 37 to the Delta variant, said Pang Xinghuo, deputy head of the municipal disease prevention and control center.

Currently, the Omicron variant outbreak has stabilized, with new cases coming from areas already under epidemic control and the risk of community spread is limited, Pang added.

Li Ang, deputy director of the Beijing Municipal Health Commission, said the clinical symptoms of patients infected with the Omicron variant are milder than those with Delta, but Omicron is more infectious.

Chen Xiaoyou, deputy director of the designated Ditan Hospital, believes that it is precisely the mild symptoms of the Omicron cases that pose difficulties to contain the epidemic in megacities.

"Many patients with mild or no symptoms will not go to medical institutions for testing. They can only be detected during routine screening," Chen said. "A longer period of hidden transmission will lead to an increase in the number of community infections."