Of the six local cases reported in Shanghai on Thursday, the first case is a logistics worker at a major hospital. Contact tracing for the man led to the discovery of another two cases－a female friend and a neighbor who is a worker at another medical institution downtown.

Heilongjiang province reported 47 new confirmed cases and 88 asymptomatic carriers of COVID-19 on Thursday, the provincial Health Commission said on Friday.

Among the patients, 10 confirmed cases and 31 asymptomatic carriers were detected in the capital city, Harbin, and all were in some way connected to a local food company.

Starting at noon on Friday, eight areas in Harbin were designated as medium-risk, according to the city's epidemic prevention and control headquarters.

Neighboring Jilin province on Thursday reported 19 confirmed cases, driving its caseload to 181. Recent local transmissions in Jilin came after the first asymptomatic carriers returned from Heilongjiang, according to provincial health officials. Seven asymptomatic carriers were identified, bringing the total to 45.

Hebei province identified 18 new local cases and three asymptomatic carriers on Thursday, the fourth day in which the number was less than 50, according to the Hebei Health Commission.

Among the new cases, 15 are in the provincial capital, Shijiazhuang, and nine of them were previously diagnosed as asymptomatic. The rest are in Xingtai, with two in Nangong and one in Longyao county.

At a news conference on Friday night, Shijiazhuang Vice-Mayor Meng Xianghong said the city detected 30 positive results for coronavirus from its third round of nucleic acid testing of its over 10.25 million residents, 25 of whom were already in centralized quarantine centers before testing positive.

"The results show that the epidemic in the city has been effectively curbed," she said, adding that no positive results were identified in low-risk areas during the citywide testing.

Zhang Yu contributed to this story.