Beijing reported 41 new locally transmitted COVID-19 cases between Friday and Sunday in various locations in the city, further complicating prevention and control efforts in the capital, a senior official said on Sunday.

The latest infections involved students, a teacher, seniors who'd been traveling in tour groups, interior decorators and a restaurant deliveryman. A preliminary epidemiological investigation showed that the virus has been spreading for a week, said Pang Xinghuo, deputy director of the Beijing Center for Disease Control and Prevention at a news conference on Sunday afternoon.

"The center has carried out the gene sequencing on four samples from the patients, and the result showed that the viruses are the Omicron variant," she said.

The investigation on one case who'd taken part in a tour of a Beijing suburb is ongoing, and the initial source has yet to be identified, Pang said.

About a quarter of the 41 cases are age 60 and above. Half of those cases had not been vaccinated.

The capital reported 21 new locally transmitted COVID-19 cases between 4 pm Saturday and 4 pm Sunday-16 confirmed patients and five asymptomatic carriers-in Chaoyang, Shunyi and Fangshan districts, according to Pang. The new confirmed cases included nine students and one deliveryman.

Previously, a school in Chaoyang had reported 10 cases between Friday and Saturday. The school was put under controlled management on Friday.

All the districts involved have taken epidemic prevention and control measures, and the city has taken steps to ensure people's daily needs are met in the controlled areas.

Yang Beibei, deputy head of Chaoyang, said starting Monday, the district will conduct nucleic acid testing for all people living and working in it.

"People in Chaoyang should try to reduce their social activities," she said. "All sports, art and training schools in Chaoyang have suspended in-person classes since Saturday."

On Saturday and Sunday, Chaoyang tested 733,647 residents in key areas.

Authorities will also strengthen specific prevention and control measures related to interior decorators and tour groups to avoid the potential for additional infections.

Chaoyang has suspended operations of all regional tour groups. The district will offer subsidies to service operators that will be affected by epidemic control measures.

Shunyi, where two new cases were reported on Sunday, has tested around 500,000 residents as of Saturday, and all the results were negative.

The district has helped 200 farming families work in bubbles to avoid financial losses that could be incurred by epidemic control measures.

On Sunday, authorities designated a residential community in Chaoyang as a high-risk area, and another a medium-risk area.