Beijing will conduct three further mass nucleic acid testings in 12 districts from Monday to Wednesday, as the Chinese capital races against the clock to contain its latest resurgence of COVID-19 infections.

The 12 districts include all urban and major suburban districts: Dongcheng, Xicheng, Chaoyang, Haidian, Fengtai, Shijingshan, Fangshan, Tongzhou, Shunyi, Changping, Daxing and the Beijing Economic-Technological Development Area, said Wang Xiao'e, a senior official from the Beijing municipal health commission.

The latest move follows three mass COVID-19 screenings that took place from Friday to Sunday in the 12 districts.

Residents in the remaining five suburban districts of Mentougou, Pinggu, Huairou, Miyun and Yanqing will need to take routine nucleic acid tests.

During mass testing on Friday and Saturday, health authorities identified multiple infections in key industries and venues, including the public transport and courier sectors as well as construction sites, Wang said.

The official said the mass screenings play an important role in helping authorities implement control measures in a timely manner, detect potential risks, and cut off virus transmission routes.

Beijing reported 55 new locally transmitted COVID-19 infections between 3 p.m. Saturday and 3 p.m. Sunday, Pang Xinghuo, deputy head of the Beijing municipal disease prevention and control center, told reporters.

A total of 45 cases were detected among people under closed management and 10 were identified in mass testing, Pang said. Hidden transmission sources in communities persist, and the virus transmission routes have yet to be completely blocked, she added.

The city currently has 18 areas classified as high-risk for COVID-19 and 26 classified as medium-risk.