China has reported its highest daily surge of new coronavirus cases since April after a food market in Beijing was closed due to a rise in local infections.
The National Health Commission confirmed there were 57 new infections in the country on Saturday, including 36 in the capital.
The new cases have sparked concerns of a second wave of Covid-19, which has infected more than seven million people worldwide and killed 432,638.
China had relaxed most of its lockdown measures after the ruling Communist Party declared victory over the disease in March.
A Beijing district is now put under lockdown after new infections were identified around a major wholesale food market.
Forty-five people out of 517 tested with throat swabs at the Xinfadi market in the city’s southwestern Fengtai district had tested positive for the coronavirus.
Chu Junwei, a district official, said none of the people who tested positive for the virus were showing symptoms of Covid-19.
The official added that 11 neighbourhoods near the market were locked down with 24-hour guards put in place.
Chu said: “In accordance with the principle of putting the safety of the masses and health first, we have adopted lockdown measures for the Xinfadi market and surrounding neighbourhoods.”
He added the district is in a “wartime emergency mode” and tourism has been banned in the Chinese capital.
The entire Xinfadi market was shut down at 3am on Saturday after two men working at a meat research centre who had recently visited the market were reported to have the virus.
The city government also said it had dropped plans to reopen schools on Monday to young pupils because of the new cases.
The market has 4,000 tenants and will be disinfected, the official Xinhua News Agency said.
Beijing authorities had earlier halted beef and mutton trading at the market and had closed other wholesale markets around the city.