All Shanghai districts will arrange massive community nucleic acid screenings every weekend through the end of July, the city's health commission announced on Wednesday.

Such weekend PCR (polymerase chain reaction) test has been mandatory for residents in districts that report any positive COVID-19 community case in the previous week.

During sample collection in these districts, temporary lockdown measures are in place, which are lifted immediately after the sample collection is completed, according to Zhao Dandan, deputy director of the commission.