Beijing will accelerate its epidemiological investigations and complete centralized quarantine work swiftly to contain the spread of COVID-19 at the community level, Xu Hejian, spokesman for the city government, said at a news conference on Tuesday afternoon.

"The epidemic situation is still severe and complicated in the city," he said. "The key industries such as delivery, logistics, sanitation, security and restaurants should raise the frequency of nucleic acid tests for employees to avoid risks of infection."

He made the statement as COVID-19 cases have continued to be found in communities outside of the locked-down and controlled zones in the capital in the past few days.

Beijing reported 35 new locally transmitted COVID-19 cases between 3 pm Monday and 3 pm on Tuesday, bringing the total number of infections to 1,591 since April 22. Sixteen districts are involved, according to Liu Xiaofeng, deputy director of the Beijing Center for Disease Prevention and Control, on Tuesday afternoon.

"Of the new infections, 32 were reported in controlled zones and three were found from mass nucleic acid tests at the community level," he said.

During an inspection tour in Beijing on Monday, Vice-Premier Sun Chunlan called for adhering to the dynamic zero-COVID policy and taking more thorough measures to cut off all COVID-19 transmission chains in communities.

"The current epidemic situation in Beijing remains controllable overall but there have been sporadic cases in a few localities," said Sun, who is also a member of the Political Bureau of the Communist Party of China Central Committee.

She urged efforts to strengthen epidemiological investigations and tracing, transferring and quarantine, to ensure the health and safety of the people, as well as the normal order of production and life.

She also called for efforts to move faster to handle clusters of cases and to properly organize nucleic acid testing to detect infections at an early date.

Beijing conducted nucleic acid tests for 15.21 million residents on Monday and the results of four tubes showed positive, involving three districts－Xicheng, Fengtai and Shijingshan－according to Wang Xiao'e, an official with the Beijing Health Commission.

Beijing is also cooperating with neighboring Hebei province to transfer close contacts.

Haidian district announced on Monday night it was transferring around 1,800 residents from its Youyi residential community, where 19 new cases have been reported recently, to Hebei's Zhangjiakou city for seven days of centralized quarantine.

People with chronic diseases, senior citizens, pet owners and students about to take school entry examinations will be allowed to stay in their homes for quarantine after being evaluated by professionals, the notice said.