Mainland China reported on Saturday the highest number of new coronavirus cases in four days, driven by a COVID-19 resurgence in the Chinese capital of Beijing.

The National Health Commission reported 21 new confirmed infections in mainland China on Friday, up from 13 a day earlier and the highest since Monday.

In Beijing, 17 new confirmed cases were reported, up from 11 a day earlier and the most since June 20.

Since June 11 when Beijing reported its first case in the current outbreak, stemming from a sprawling wholesale food centre in the southwest of the capital, 297 people in the city of more than 20 million have contracted the virus.

Mainland China reported four new so-called imported cases on Friday, infections linked to travellers arriving from abroad. That compares with two cases a day earlier.

That took the cumulative number of confirmed cases in mainland China to 83 483.

Mainland China reported 12 new asymptomatic patients, who tested positive for COVID-19 but showed no clinical symptoms such as a fever, up from five a day earlier.

The national health authority does not include asymptomatic patients in its tally of confirmed cases.

The death toll stood at 4 634, unchanged since mid-May.