Wuhan will test all 11 million of its residents for coronavirus after the place where the virus emerged in late 2019 confirmed its first cases of the Delta variant.
The measures come after the central Chinese city reported three domestically transmitted cases on August 2 - the first local infections in more than a year.
Wuhan, which gave the world its first glimpses of lockdowns and mass testing, had reported no local coronavirus cases since mid-May last year.
China is currently seeing one of its biggest outbreaks in months, with 300 cases detected in 10 days.
“To ensure that everyone in the city is safe, city-wide nucleic acid testing will be quickly launched for all people to fully screen out positive results and asymptomatic infections,” Li Qiang, an official in Wuhan told a news briefing.
The outbreak is believed to have begun in the provincial capital of Nanjing, with the Delta variant mostly likely introduced on a flight from Russia, officials have said.
Since then numerous cities in southern China and a few in the north, including Beijing, have reported infections. The tally of locally transmitted cases in China since July 20, when the first Nanjing infections were found, stood at 414 as of Monday.
The Delta variant poses new risks for the world’s second-biggest economy as it spreads from the coast to inland cities. Authorities in numerous cities have launched mass testing to identify and isolate carriers.
China reported on Tuesday 90 new confirmed cases had been recorded the previous day compared with 98 on Sunday, according to the National Health Commission (NHC).
As of August 2, mainland China had recorded 93,193 confirmed cases, with the cumulative death toll unchanged at 4,636.
Additional reporting by Reuters.