Shanghai is quietly shutting schools and other public venues as officials try to rein in a Covid flare-up after a week-long national holiday.
Measures are also being taken in other major Chinese cities as case numbers rise.
Several schools in the city have suspended in-person teaching as the fear of infection spread grows, according to parents and other people on social media. Schools in the central city of Xian have also done so, local outlets reported.
At least five Shanghai districts have closed entertainment venues, including cinemas, bars and gyms, in an effort to stamp out transmission. Internet cafes are also closed in at least three downtown districts.
All 16 districts in the city, which is home to more than 26 million people, are to conduct mass testing at least twice a week until November 10, authorities said.
There is no citywide school shutdown, officials confirmed on Sunday, assuaging fears after social media speculation that the measure would be rolled out. But the creeping measures, as well as as lockdowns in individual neighbourhoods and residential compounds have left residents on edge.
Other cities in China have also increased testing as the country recorded its highest levels of cases since August.
The measures follow China's Golden Week, which ended on Friday. The celebrations include National Day, on October 1, commemorating the founding of the republic in 1949.
Many Chinese cities advised residents to avoid unnecessary trips for the public holidays. The government reported revenue well below pre-pandemic levels for the holiday month, with public spending reaching a seven-year low in the period, usually a peak time for travel.
It also comes ahead of a key political congress in Beijing on Sunday, where President Xi Jinping, in office since 2013, is expected to extend his leadership.
The ruling Communist Party's congress happens once every five years.
The government reaffirmed its "zero-Covid policy" ahead of the meeting.
China, where the virus was first recorded in late 2019, is one of the last countries to still enforce strict Covid-related measures, often announced with little notice.
The entire region of Xinjiang, home to 22 million people, recently banned all residents from leaving only weeks after it had begun relaxing restrictions from a stringent extended lockdown. Hundreds of tourists were stranded in an airport in the south-west province of Yunnan after authorities imposed a snap lockdown.