Delivery workers hand parcels to people in a residential compound in Beijing's Xicheng district on Wednesday. Restrictions on access to all communities have resumed as the city increased the level of its COVID-19 emergency response. CHEN ZHONGHAO/XINHUA

"Currently, the city has the ability to test an average of 400,000 people per day, and we plan to step up testing capacity in the coming days," said Zhang Qiang, a member of the city's epidemic-control office, on Wednesday.

The capital has tested about 356,000 people since Saturday, he said.

Also, to help residents who have been to Xinfadi and other high-risk areas report their information quickly and easily, many districts in Beijing including Xicheng have released hotline numbers to communities so social workers and volunteers can visit the residents to collect information.

The city also has suspended group events such as wedding receptions and banquets to contain the further expansion of COVID-19.

Beijing's education authorities have also responded quickly, suspending on-campus classes and requiring all students to return home and study online starting on Wednesday.

While many markets have been shut down for disinfection, the major supermarkets and stores across the city are capable of supplying the needs of residents, said Wang Hongcun, an inspector from the Beijing Municipal Commerce Bureau.

Up to 64 stores in Beijing had stock shortages on Sunday, he said, adding that the number was reduced to six on Tuesday as the authority continued to work to ensure transportation of vegetables and other daily necessities to the city.