Cities in eastern China tightened COVID-19 curbs on Sunday as coronavirus clusters emerge, posing a new threat to China's economic recovery under the government's strict zero-COVID policy.

Wuxi, a manufacturing hub in the Yangtze Delta on the central coast, halted operations at many public venues located underground, including shops and supermarkets. Dine-in services in restaurants were suspended, and the government advised people to work from home.

City authorities urged residents not to leave Wuxi unless necessary, after reporting 42 new asymptomatic cases on Saturday.

China continues to try to stamp out new infections as part of the strict approach taken in the country where the coronavirus was first detected in late 2019. But the lockdowns and other measures have taken a heavy toll on the world's second-biggest economy.

Si county in Anhui province locked down its 760,000 residents and suspended public traffic as it reported 288 cases on Saturday. Anhui accounted for most of China's new infections, reporting 61 symptomatic and 231 asymptomatic cases for Saturday.

Mainland China recorded 473 new COVID-19 cases, of which 104 were symptomatic and 369 were asymptomatic, the National Health Commission said on Sunday. That compares with 268 new cases a day earlier - 72 symptomatic and 196 asymptomatic infections, which China counts separately.

Yiwu, China's export capital for small commodities, cancelled flights to the capital, Beijing, for an unspecified period, state TV said, citing COVID prevention measures. Yiwu has reported three COVID cases in the past week.

Shanghai, China's most populous city and financial hub, reported one positive case outside of quarantine areas in the city from midnight to 5 p.m. on Sunday (1600 GMT on Saturday to 0900 GMT on Sunday), officials told a news press conference.

The city lifted a lockdown on June 1 after two months of shutdown that hit output and consumer spending.

There were no new deaths, keeping the nation's death toll to 5,226. As of Saturday, mainland China had confirmed 225,851 cases with symptoms.

For Saturday, Beijing reported no new local cases, and Shanghai reported two local symptomatic cases, according to local government data.