Parts of Tibet are running mass Covid-19 testing on Tuesday, including the Chinese autonomous region's two largest cities, to fight a rare flare-up, while clusters were growing in tropical Hainan and in Xinjiang in China's west.
Subvariants of the highly transmissible Omicron are challenging China's strategy of swiftly blocking the spread of each nascent cluster. Regions that have seen relatively few cases for more than two years now battling outbreaks, raising the risk of persistent tight restrictions as the economy weakens.
Mainland China reported 828 new domestically transmitted cases for Aug 8, official data showed on Tuesday. Over 70% of those cases were found in Hainan, one of the country's most popular tourist destinations, as well as Xinjiang, while the rest were reported across more than a dozen provinces and regions.
In Hainan, millions of residents are under lockdown across several cities and towns, allowed out only for necessary reasons such as Covid tests, grocery shopping and essential job roles. Around 178,000 tourists were also stranded in the southern island province, according to state media reports.
Provincial authorities must adopt all measures to achieve by Friday "Covid zero at the community level" where no new cases emerge in communities outside quarantined areas, Hainan's government said in a statement late on Monday.
Hainan's success in containing smaller clusters in April and July has resulted in complacency among officials and residents, one provincial health official said.
"We still have many shortcomings and weaknesses in Covid epidemiologic investigation, testing and treatment," Zhou Changqiang, the head of Hainan's health commission, told state television in a programme that aired late on Monday.
In Tibet, which had previously found only one symptomatic Covid infection in more than 900 days, local authorities reported one local patient with confirmed symptoms and 21 asymptomatic infections on Aug 8.
Lhasa, Tibet's biggest city and provincial capital, has suspended large events and closed various entertainment and religious venues.
Tibet's second-largest city Shigatse has entered three days of curbs during which people are banned from entering or leaving, with many businesses suspended.
Lhasa and Shigatse are running a fresh round of mass testing, and the second round would begin on Wednesday, state television said on Tuesday.
In Tibet's Ngari prefecture, three towns have started three rounds of mass testing, while the remaining towns are in their first round, state television said.
As of Aug 8, mainland China had logged a cumulative 231,665 cases with symptoms, including both local patients and those arriving from outside the mainland.
There were no new deaths reported on Aug 8, keeping the nation's fatalities at 5,226.
China's capital Beijing, along with financial hub Shanghai and the southern technology centre of Shenzhen reported zero new local cases.