Children play at a square in Wuhan, capital of central China's Hubei province, April 1, 2020. (XIAO YIJIU / XINHUA)

BEIJING/WUHAN - China will step up targeted screening of people infected with COVID-19 caused by a novel coronavirus but showing no symptoms, a health official said Thursday.

The surveillance for asymptomatic infections will be expanded to include close contacts of confirmed COVID-19 patients and asymptomatic patients, cluster outbreaks, and key areas and populations with high risk of infections, Wang Bin, an official with the National Health Commission, said at a press conference in Beijing.

Medical institutions will, with the help of communities and fever clinics, increase efforts to identify asymptomatic patients and put them under centralized quarantine in a timely manner, she said.

The National Health Commission said it received reports of 35 new confirmed cases on Wednesday, all of which were imported

Wang said epidemiological investigations will be promptly conducted for asymptomatic patients, and relevant information will be released openly and transparently.

The identified asymptomatic patients will be subject to centralized medical observation for two weeks, and will be released after testing negative for the virus for two consecutive times, she added.

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The commission said Thursday no new domestically transmitted cases of COVID-19 were reported on the Chinese mainland on Wednesday.

The commission said it received reports of 35 new confirmed cases on the mainland on Wednesday, all of which were imported, bringing the total number of imported cases to 841.

A total of 26 provincial-level regions on the  mainland had reported imported COVID-19 cases, the commission said.

No deaths had been reported from the imported cases, said the commission.

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Also on Wednesday, six deaths and 20 new suspected cases were reported on the mainland, according to the commission. All the newly reported deaths were in Wuhan, the provincial capital of Hubei province, and all the new suspected cases were imported.

On Wednesday, 170 people were discharged from hospitals after recovery on the mainland, while the number of severe cases decreased by 37 to 429.

55 new asymptomatic COVID-19 cases were reported on the mainland Wednesday, including 17 imported ones

The overall confirmed cases on the mainland had reached 81,589 by Wednesday, including 1,863 patients who were still being treated, 76,408 patients who had been discharged after recovery, and 3,318 people who died of the disease.

The commission said that 153 people were still suspected of being infected with the virus, and 20,072 close contacts were still under medical observation. On Wednesday, 1,898 people were released from medical observation.

Also on Wednesday, 55 new asymptomatic COVID-19 cases were reported on the mainland, including 17 imported ones. Nine asymptomatic cases, all imported ones, were re-categorized as confirmed infections, and 338 were discharged from medical observation, according to the commission.

The commission said 1,075 asymptomatic cases were still under medical observation, including 226 from abroad.

In Hubei, 37 asymptomatic COVID-19 cases were confirmed Wednesday, bringing the total to 721, all of whom had been put under medical observation by the end of Wednesday.

Hubei has so far reported 67,802 confirmed COVID-19 cases in total, including 50,007 in Wuhan.

READ MORE: Local COVID-19 cases drop to under 1,500 on mainland

By Wednesday, 765 confirmed cases including four deaths had been reported in the Hong Kong Special Administrative Region (SAR), 41 confirmed cases in the Macao SAR, and 329 in Taiwan including five deaths.

A total of 147 patients in Hong Kong, 10 in Macao and 45 in Taiwan had been discharged from hospitals after recovery.