Beijing will require all residents living and working in four districts and people in communities where COVID-19 cases have been reported during the past seven days to take three consecutive nucleic acid tests on Thursday, Friday and Saturday to curb the epidemic and cut transmission, a senior official said on Wednesday.

The districts include Xicheng, Haidian, Fengtai and Fangshan, said Wang Xiao'e, an official with the Beijing Health Commission, at a news conference on Wednesday afternoon.

Other districts in Beijing will conduct regular nucleic acid tests for residents according to previous regulations. Staff in key industries including logistics and public transportation should take regular tests as required.

"The city has conducted several rounds of mass nucleic acid tests since April 25, which has effectively helped to discover the infection risk and cut the virus spread during this round of the outbreak," Wang said.

According to the commission, the city collected samples from around 20.74 million residents for tests on Tuesday and four tubes tested positive in three districts — Fangshan, Haidian and Fengtai.