The Chinese capital issued a fresh coronavirus alert on Thursday after it reported 21 local COVID-19 infections a day earlier, three of which were from a high school and the rest from a university, health officials said.

In view of the fresh outbreak, Beijing's health officials asked residents to stay put during the upcoming Mid-Autumn festival holiday on Saturday, official media reported.

According to the Beijing Municipal Health Commission, there have been three confirmed cases screened out from the community level in Beijing's Haidian district.

The three, who tested positive are classmates and live in the student dormitories of the high school affiliated to Minzu University of China, state-run Global Times reported on Thursday.

It is mandatory for the city's 21.5 million population to undergo COVID-19 tests on alternate days.

The high school has traced 570 close contacts and has been designated as a high-risk area since the three cases have been staying on the campus since September 1.

The other 18 cases were reported from the Beijing University of Chemical Technology (BUCT).

According to the university's deputy head Wang Feng, BUCT's Changping campus collected 17,853 test samples on Wednesday, all of which turned negative.

Meanwhile, China's National Health Commission reported on Thursday that 241 new local confirmed COVID-19 cases, including 69 in earthquake-hit Sichuan province and 1,093 asymptomatic cases were reported on Wednesday.

China, where the coronavirus surfaced in Wuhan in December 2019, implements a strict Zero-COVID policy' under which cities go into periodic lockdowns to contain the spread of the virus adversely impacting the businesses and supply chains.

China's Sichuan province has banned the entry of unauthorised people to earthquake zones and ordered daily testing of survivors and rescue workers as it struggled to battle the virus.

A 6.8 magnitude earthquake shook the province on Monday. So far, the death toll stood at 74, with another 26 people still missing.

PTI