China reported 55 new locally transmitted cases on Monday as an outbreak of the fast-spreading Delta variant reached over 20 cities in more than a dozen provinces.
The Wuhan cluster came after the official daily tally was released, but it was confirmed by state media which said the infections had been traced to a train station.
“The seven were identified as migrant workers,” Xinhua reported, citing Covid-19 prevention and control officials.
Major cities including Beijing have now tested millions of residents while cordoning off residential compounds and placing close contacts under quarantine.
Authorities in the capital met and agreed on the need to “raise vigilance, take strict precautions and defend (the city) to the death, sparing no expense,” in comments put out by the Beijing government.
Elsewhere, over 1.2 million residents were placed under strict lockdown for the next three days in the central city of Zhuzhou in Hunan province Monday, as authorities roll out a citywide testing and vaccination campaign, according to an official statement.
“The situation is still grim and complicated,” the Zhuzhou government said.
China had previously boasted of its success in bringing domestic cases down to virtually zero after the coronavirus first emerged in Wuhan, allowing the economy to rebound.