The infection clusters in Beijing continue to yield more cases, making up the bulk of the daily caseload.

Beijing reported 49 new locally transmitted COVID-19 cases between 3 pm Tuesday and 3 pm Wednesday, bringing the total number of infections to 1,218 since April 22. Fifteen districts are involved, according to Liu Xiaofeng, deputy director of the Beijing Center for Disease Prevention and Control, who spoke at a news conference on Wednesday.

Thirty-five new infections among the 49 cases were related to recent clusters, involving a market, a subway renovation project, a bus station and a branch of a logistics company.

By Wednesday afternoon, the major cluster from the Yuegezhuang wholesale market had resulted in 78 cases, and the cluster from the logistics company had led to 50 people being infected, Liu said.

Fangshan district reported a new risk location involving a branch campus of Beijing Institute of Technology, which has 670 teachers, students and other staff.

Zhang Mingzhi, a spokesman for Fangshan district, said all of those people would be transferred to centralized quarantine facilities.

Of the new infections, 45 were reported in controlled zones, and four were found from mass nucleic acid testing at the community level, according to the Beijing CDC. One of the confirmed cases had not taken any nucleic acid tests recently, which has resulted in the virus spreading.

To further curb the epidemic and stem transmission, Beijing will require all residents living and working in four districts and people living in subdistricts where COVID-19 cases have been reported during the past seven days to take three consecutive nucleic acid tests from Thursday to Saturday, Wang Xiao'e, an official with the Beijing Health Commission, said at the news conference on Wednesday afternoon.

The districts requiring testing are Xicheng, Haidian, Fengtai and Fangshan, while the other districts will conduct regular nucleic acid tests for residents as previous regulations required.

Meanwhile, the neighboring city of Tianjin reported 16 new locally transmitted cases and 39 asymptomatic cases on Tuesday.

Citywide testing for Tianjin's 13 million residents on Sunday revealed four people tested positive in Dongli and Beichen districts on Sunday evening. Another two rounds of tests were conducted in the two districts on Monday and Tuesday, with no new confirmed cases found, according to the Tianjin Health Commission.

Preliminary evidence indicated the cases might be related to cold chain logistics for imported food.

Gene sequencing found the infections to be a type of Omicron variant different from other cases and "not related to the outbreak of Beijing's Omicron variant this month", according to Gu Qing, director of the commission.