China reported 5,280 new Covid-19 cases on Tuesday, more than double the previous day's tally and the highest daily count since the start of the pandemic.
The northeastern province of Jilin was worst hit, accounting for more than 3,000 cases, according to the National Health Commission.
Since the coronavirus first emerged in the central city of Wuhan in late 2019, China had successfully suppressed large-scale outbreaks through its strict "zero-Covid" strategy, which involved hard lockdowns that confined huge sections of the population to their homes.
But Tuesday was the sixth day in a row that more than 1,000 new cases were recorded in the world's second-biggest economy.
At least 11 cities and counties nationwide have been locked down because of the latest surge, including the southern tech hub of Shenzhen, home to 17 million people.
China’s financial hub of Shanghai has also seen infections rise to their highest ever, prompting the halt of bus services from other provinces and the discussion of diverting international flights. The city has already switched to home-schooling for students from kindergarten to middle school, while several hospitals in the city have suspended outpatient services.
Elsewhere, Dongguan, a key manufacturing city in the southern province of Guangdong, suspended operations at factories in areas where the virus is circulating.
The growing clusters in some of the country’s key economic zones are set to test China’s Covid Zero playbook, which typically relies on mass testing and hardcore lockdowns to stamp out infections. Until now, officials have largely resisted extreme lockdowns in major cities, and instead have deployed more targeted responses.
With inputs from agencies
