Medical workers are going all out to treat critical and severely ill patients with COVID-19 while sparing no effort to halt the spread of the virus in Guangzhou, capital of Guangdong province, a local senior health official said on Thursday.

Zhang Yi, deputy director and spokeswoman of the Guangzhou Health Commission, said an expert consultation system has been set up in accordance with patients' health conditions and they are being treated with traditional Chinese and Western medicines.

The city reported 275 local confirmed cases and 8,486 asymptomatic carriers on Wednesday, including one critical and one severe patient.

It is the first time the city has reported cases in intensive care units. The tally from the latest outbreak has risen to more than 45,000 since late October.

The critical patient is an 82-year-old woman, who has coronary heart disease, thoracic malformation, chronic bronchitis and is bedridden, while the severe patient is a 62-year-old man who has severe high blood pressure, coronary heart disease and long-term side effects from a stroke.

Both are in stable condition after treatment in a designated hospital, Zhang said.

"Hospitals have implemented 'one case, one treatment' for special cases with severe chronic diseases and pregnant women," she added.

Haizhu, the hardest-hit district in Guangzhou, reported 8,582 of the city's 8,761 infections on Wednesday, with 92.6 percent detected in Haizhu's Fengyang, Nanzhou and Huazhou subdistricts.

Zhang Zhoubin, Party secretary of the Guangzhou Center for Disease Control and Prevention, said the real-time transmission index — a number that determines how many people can be infected by another person — in Haizhu had been reduced to 1.5 by Thursday from 2.2 recorded a week ago, and it has been fluctuating between 1.4 and 1.5 in the last four days.

"That indicates the prevention and control measures taken in the past week are effective in curbing the spread of the virus in Haizhu," he said.

"The still-growing number of cases detected in Haizhu reflects the reality that Haizhu has a large number of infected people. And that is why the real-time transmission index has dropped, but many infections are still detected in the district," he added.

In Beijing, the epidemic situation is still developing and the risk of hidden spread at the community level still exists, Liu Xiaofeng, deputy director of the Beijing Center for Disease Prevention and Control, said at a news conference on Thursday.

Between midnight and 3 pm on Thursday, Beijing reported 218 locally transmitted COVID-19 infections, with 23 detected at the community level.

"The current outbreak has involved several densely populated industries and places, including catering, schools, urban villages and construction sites," said Liu. "We must deal with cluster infections in a scientific, precise and efficient way."

Staff members should strengthen risk screening in densely populated places as well as completely implement measures, including health code scanning, body temperature measurement, nucleic acid test checking and public disinfection, Liu added.

He urged residents to maintain good hygiene habits and avoid unnecessary gatherings to reduce the risk of transmission.

In Chongqing, the proportion of newly confirmed COVID-19 cases via community transmission on Tuesday was 36.2 percent — a decrease of 13 percentage points from Monday, according to the local health commission.

The decrease means the policy of coordination that was implemented in the city's central urban districts has worked to some extent, said Li Pan, deputy director of the commission, at a news conference on Wednesday.

The Chinese mainland on Wednesday reported 2,328 locally transmitted confirmed COVID-19 cases and 20,804 local asymptomatic carriers, the National Health Commission said Thursday.

Du Juan in Beijing, Deng Rui and Tan Yingzi in Chongqing contributed to this story.