Both the number of new locally transmitted COVID-19 infections and cases detected at the community level in Beijing have shown a significant increase in recent days, with further expansion of affected areas, a senior official said on Sunday.

"We are still facing a grim and complicated epidemic prevention and control situation, as the risk of hidden spread at community level still exists," Xu Hejian, spokesman of the municipality, said at a news conference on Sunday. "Furthermore, we have also seen an increase of confirmed cases reported among those who returned to the capital."

"Related departments are required to optimize and improve epidemic prevention policies and control measures for those who return to Beijing, including strengthening risk screening and nucleic acid testing," he added.

Between midnight and 3 pm on Sunday, Beijing reported 516 locally transmitted COVID-19 infections, 470 of which are asymptomatic carriers. All 46 confirmed patients were diagnosed as mild cases, according to the city's health commission.

Among them, 381 were found among those under quarantine and the other 135 were detected at the community level.

Chaoyang district, the hardest-hit area in the capital, reported 357 cases.

"Residents in the district are still being suggested not to leave their area unless it's necessary for the coming working day," Yang Beibei, deputy head of Chaoyang district, said at the conference. "Flexible work, including the use of telephone, Internet and video conferencing are encouraged."

She also urged residents to avoid unnecessary gatherings and keep a safe distance outside to reduce the risk of transmission.

Beijing Ditan Hospital reported a COVID-19 death on Saturday.

"The 87-year-old male patient was transported to the hospital on Nov 13 and was diagnosed as a mild case," Jin Ronghua, director of the hospital, said at a news conference on Sunday morning. "We immediately carried out a multidisciplinary consultation with a group of experts and gave anti-infection and symptomatic support treatment."

The condition of the patient continued to deteriorate due to underlying diseases, including high blood pressure, cerebral infarction and cerebellar atrophy, and the patient died on Saturday due to pulmonary infection, respiratory failure, sepsis and septic shock.

As of 7 am Sunday, there have been 608 infections receiving medical treatment in the hospital, including 325 high-risk patients.