Xiaocun village in Xiaohongmen township in Beijing's Chaoyang district has been named a medium-risk area for COVID-19 starting Wednesday, a disease control and prevention official from the Chinese capital said.

The village is the only medium-risk area for COVID-19 in Beijing, according to Pang Xinghuo, deputy director of the Beijing Center for Disease Control and Prevention.

"As 4 pm on Wednesday, the village had reported a total of three confirmed cases in the previous 14 days," she said.

Beijing added a total of nine COVID-19 infections over the 24 hours ending at 4 pm on Wednesday, including 8 patients and an asymptomatic carrier, Pang said.

As of Wednesday, a cluster infection which began at a school in Beijing's Dongcheng district has caused 15 persons, including seven students and eight parents, to be infected with the novel coronavirus, Pang said.

Gene sequencing indicates those patients were infected with Omicron and the cases are highly similar to a viral sequence uploaded overseas in January.

The input of multiple cases from outside the city has increased Beijing's pressure to curb the spread of the pandemic, she said.

She urged a tightening of COVID-19 prevention and control measures in the weeks to come and priorities given to local schools, medical institutions, railway stations and ports, with testing for both people and objects.

Xu Hejian, a spokesman for the Beijing municipal government, said all arrivals have been required to show a negative nucleic acid tests from the 48 hours before they arrived in or returned to Beijing.

"They are also required to have another nucleic acid test within 72 hours of their arrival in Beijing," he said.

In Beijing's neighboring city Langfang in Hebei province, a total of 257 infections, including 32 confirmed cases and 225 asymptomatic carriers, were detected on Tuesday.

All carriers have been sent to designated hospitals for further medical observation and treatment and they were in stable condition, local health authorities said on Wednesday.

As the end of Tuesday, Langfang had reported a total of 708 infections, including 104 confirmed cases and 604 asymptomatic carriers, in this outbreak, local health authorities said.

A large number of people commute between Beijing and Langfang, as the Hebei city borders Beijing's Daxing and Tongzhou districts.

To cut the virus' transmission, some districts in Langfang have prohibited all vehicles and personnel from entering or leaving except those necessary for the national economy and people's livelihoods, epidemic prevention and control and emergency rescue.