Of the new infections, 18 were in the far western region of Xinjiang and one was in Dalian city in the northeastern Liaoning province, according to a statement by the National Health Commission. The other three were imported cases.
The Dalian case involved a 58-year-old man working at a seafood processing company. Multiple samples collected from the company, including frozen food, processing workshop, canteen and office building also tested positive, state media said.
China reported 31 new asymptomatic patients, or those showing no symptoms, up from 22 a day earlier.
On Thursday, Dalian reported two new locally transmitted cases and 12 asymptomatic ones, all close contacts of the case from Wednesday, state media said citing Dalian government.
Earlier this month, customs in Dalian found the coronavirus in the packaging of frozen shrimps imported from Ecuador. China suspended imports from three Ecuadorean shrimp producers after detecting the virus.
Dalian, with a population of nearly 7.0 million, plans to conduct nucleic acid testing for 190,000 people in the city, state media said.
As of Wednesday, mainland China had 83,729 confirmed coronavirus cases, the health authority said. The COVID-19 death toll remained at 4,634.