Shanghai reported one locally transmitted COVID-19 confirmed case and one asymptomatic infection on Thursday, the Shanghai Health Commission said at a news briefing.

Both were found during regular nucleic acid test screening in the city and are not related to the ongoing outbreak in Hainan province, according to Zhao Dandan, deputy director of the Shanghai Health Commission.

A total of 721 close contacts of the two patients have been identified and put under quarantine as of 4 pm Thursday, Zhao said.

Epidemiological investigations showed that both cases had been to the Weiqiang Foot Massage Store in Xuhui district and an entertainment store specializing in chess and card services. Both venues have been placed on file for investigation due to their unauthorized business activities and failure to strictly implement the epidemic prevention and control measures, said Wang Hongwei, deputy governor of Xuhui district.

"The district will strengthen the supervision, inspection and centralized rectification of key places. Any business that violates the relevant requirements of epidemic prevention shall be investigated and punished according to laws and regulations," Wang added.

According to Zhao, Shanghai has received five flights from Hainan province with a total of 845 passengers, who undergo three days of quarantine at designated hotels and four days of quarantine at home. No infections have been reported so far.