Shanghai reported six community COVID-19 cases on Thursday, including three staff at a downtown hair salon which had served more than 400 customers since it reopened on June 1.

The city declared four more areas in downtown as medium-risk spots. A massive polymerase chain reaction (PCR) screening will be launched in seven districts over the weekend, with temporary lockdown measures in place during the sample collection, according to the Shanghai Health Commission.

Scattered community infections have been detected continuously since June 1, when the city lifted the two-month-long lockdown, mainly at some old residential compounds and service venues in downtown, Zhao Dandan, deputy director of the commission, revealed.