After a small new cluster of Covid cases appeared, the Chinese city of Qingdao will test all nine million residents over a five-day period.
The city reported six new confirmed cases and six new asymptomatic cases, all of which were traced to the Qingdao Chest Hospital, which is a facility used to treat imported Covid-19 cases.
So far, the city has carried out more than four million tests of the nine million planned tests on residents.
Authorities have also locked down the Qingdao Chest Hospital and some residential areas where patients who tested positive for Covid-19 cases live to prevent further spread.
Throughout the pandemic, Qingdao city had remained relatively Covid free, with only 65 confirmed cases and one death.