Beijing authorities reiterated it would spare no effort to continue the strategy of fighting imported cases and a rebound in local cases in the months to come, as the Chinese capital still faces a grim and complex situation in the fight against COVID-19.

"While the pandemic is still spreading quickly in foreign nations around the world and outbreaks are being reported in some domestic cities, strict prevention and control measures will remain, including case investigation and risk group screening to help curb the spread of the novel coronavirus in Beijing," said Liu Xiaofeng, deputy director of the Beijing Municipal Center for Disease Prevention and Control, at a news conference in Beijing on Tuesday, when the city reported four new locally transmitted confirmed COVID-19 patients in the first 11 hours on Tuesday.

All the patients, including two reported in Fengtai district, one in Haidian district and another in Xicheng district, were detected when they returned to Beijing after participating in a training course organized by a company outside the capital city from Thursday to Sunday, Liu said.

All patients returned to Beijing by train, said Liu.

Liu urged residents to actively cooperate with relevant departments to curb the spread of the coronavirus in the city, which will soon organize the 2022 Winter Paralympics.

Lin Hang, deputy director of Haidian district, said relevant departments have temporarily closed the community where the district's confirmed case lives for strict management starting at 2 am on Tuesday, after the patient was confirmed.

And an epidemiological investigation and nucleic acid tests were immediately launched simultaneously, she said.