China on Monday sealed 10 more neighbourhoods in Beijing after a spate of fresh coronavirus cases linked to a food market sparked fears of a new wave of infection, AFP reported.

Authorities on Saturday had closed the Xinfadi market, the country’s largest wholesale market, for meat and vegetables in Beijing after over 40 people associated to the market tested positive for the virus. Eleven other neighbourhoods in the vicinity of the market were also sealed, and all tourism and sporting events were cancelled.

A city official, Li Junjie, at a press conference on Monday said that fresh cases had also been found in a second wholesale market in the Haidian district. Authorities temporarily shut down the market and all nearby schools were ordered to be closed, as people living in 10 communities around the market were placed under a lockdown, Junjie added.

So far, the local government has closed six wholesale markets and made alternate arrangement for vegetable supplies to the retail stores.

Meanwhile, China on Monday began mass testing hundreds and thousands of people who had visited the Xinfadi market since May 30. Authorities are also stepping up efforts to trace those who have visited the market, with companies and neighbourhood communities messaging staff and residents to inquire about their recent movements, according to AFP.

The authorities have conducted the nucleic acid test on 29,386 people so far, Goa Xiaojun, spokesperson for the Beijing Health Commission said, according to PTI. Out of these, 12,973 samples came negative, while results for the remaining swabs are pending, he added.

All the hospitals in Beijing have been ordered to perform nucleic acid and antibody tests, a computed tomography scan and a routine blood test on patients with fever, Xiaojun said.

The Beijing Municipal Health Commission said that Beijing reported 36 new cases of the coronavirus which are domestically transmitted, and six new asymptomatic cases on Monday. There were also 10 imported cases on Monday, which have accounted for the majority of China’s cases in recent months as overseas nationals return home.

In addition to the new cases reported in Beijing, the National Health Commission said there were three confirmed cases in Hebei province – once the epicentre of the disease.

In total, 177 more people were ill with the disease in China as of Monday, which is the highest since early May. Of these, two are reported to be in a severe condition. With this, the total tally of Covid-19 infections in the country reached 83,181. The toll from the disease is 4,634.

On Sunday, Yang Peng, a researcher from Beijing’s Centre for Diseases Prevention and Control, said that it has been more or less determined that the virus found on the samples from the Xinfadi market is related to strains China has seen from imported cases. The genome sequencing showed that the coronavirus came from Europe, he added.

The sudden increase in cases has sparked concern that China may be on the cusp of a rebound of Covid-19, belying predictions made by experts that a second wave may hit the country from October.