Authorities in the Chinese city where the coronavirus pandemic first broke out are planning to test all 11 million residents in the next 10 days, local media have reported.
No official announcement has been made, but district officials in Wuhan confirmed receiving orders from the city's coronavirus taskforce, the reports said.
The order came after the discovery last weekend of a cluster of six infected people at a residential compound in the city, the first new cases in more than a month.
China has moved quickly to snuff out new outbreaks wherever they pop up, even as it relaxes restrictions on the movement of people and reopens public attractions to limited numbers of visitors.
Jilin province, which borders North Korea, has suspended all public transport and imposed other restrictions as it battles a fresh outbreak.
In neighbouring Heilongjiang province, which dealt with its own outbreak recently, the city of Harbin is quarantining anyone coming from Jilin for 14 days and banning them from hotels.
A major state-owned news website, Jiemian, said it had obtained an implementation plan for the city's Wuchang district that said all residents should be tested by May 20, or in about a week's time.
Wuhan was the area hit hardest by coronavirus in China. Of the 4,633 reported deaths nationwide, 4,512 were in Hubei province, including 3,869 in Wuhan, the provincial capital.
China imposed a lengthy lockdown on most of Hubei in late January to stem the spread of the virus. People were forbidden from entering or leaving the province, public transport was suspended and residents were mostly restricted to their homes.
The lockdown was lifted outside Wuhan after two months, and in Wuhan itself on April 8, after two and a half months.
The new cases appear to have shocked city officials into action. They dismissed the Communist Party secretary of the neighbourhood where the cluster was found for poor management of the residential community, the official Xinhua News Agency said.
The order said the testing should focus on the elderly, densely populated areas and those with mobile populations, according to the media reports.
One expert at Wuhan University told the Global Times newspaper that three million to five million residents have already been tested, which could leave up to eight million others for a citywide test.