Millions have been forced back into lockdown in China as the Delta variant hits 20 cities in the country.
More than a dozen provinces, including Wuhan where the virus first emerged, have been affected by the hugely infectious variant.
The country reported 55 new locally transmitted infections including seven positive cases in Wuhan.
It came after China's official daily numbers were released, state media said infections had been traced to a train station.
Chinese media outlet Xinhua said: "The seven were identified as migrant workers."
Earlier today The Mirror told how 300 cases had been detected in the last 10 days a the Delta variant spread.
Zhong Nanshan, China's top respiratory diseases specialist reportedly expressed grave concern over the spread of the virus in the central city of Zhangjiajie after eight more infections were confirmed.
The outbreak has been fuelled by the more contagiousvariant, and triggered fresh travel restrictions and testing for millions of residents.
Fifteen provinces and municipalities have now confirmed cases, and 12 of those are linked to an outbreak that began in the eastern city of Nanjing, the BBC reported.
Major cities are reported to have tested millions of residents and cordoned off residential areas.
Authorities agreed on the need to raise vigilance and take more precautions, according to the Beijing government.
Rail, bus and air links in areas with positive Covid cases have been cut and tourists barred during the peak summer holiday season.
Residents have been told not to leave "unless necessary".
The capital's Changping district locked down 41,000 people in nine housing communities last week.
Elsewhere, more than 1.2 million residents were placed under strict lockdown for the next three days in the central city of Zhuzhou in Hunan province Monday.
Authorities are also rolling out a citywide testing and vaccination campaign, but the government has admitted the situation is grim.
The republic had boasted of its success in bringing domestic cases down to virtually zero which allowed the economy to rebound.
And images of partygoers at gigs and nightclubs were looked upon jealousy from around the globe.
The latest outbreak, however, has been linked the city of Nanjing where nine cleaners tested positive last month prompting more than 360 domestic cases reported in the past two weeks.
In the tourist destination of Zhangjiajie, 15 million residents were locked down on Friday
People who have recently travelled from Nanjing or Zhangjiajie are being traced and holidaymakers have been urged not to travel.
Fresh cases were also reported in Hainan and Henan province, national health authorities said.
All 10 million residents have been ordered to get tested after more than 30 cases were detected.
The number of people who have tested positive for the virus in China now stands at 93,103, with 1,091 active cases, and 4,636 deaths.