BEIJING - Mainland China reported 18 new COVID-19 infections on May 15, up from 14 a day earlier, the national health authority said on Sunday.

In its daily bulletin, the National Health Commission (NHC) said four of the new cases were local infections in the northeastern province of Liaoning. The rest originated overseas.

The authority has sent a working group to Liaoning to guide its COVID-19 control efforts, while schools and kindergartens in the province's Bayuquan district have been temporarily shut from Sunday, official news agency Xinhua said.

On Friday, the NHC reported China's first local transmissions in more than three weeks, with a patient surnamed Li, who travelled to Anhui from Liaoning, identified as the source. 

The number of new asymptomatic cases, which China does not classify as confirmed cases, was 19 on Saturday, down from 25 the previous day.

The total number of confirmed COVID-19 cases in Mainland China now stands at 90,847, while the death toll remained at 4,636.

China performed about 12.4 million vaccinations on Saturday, taking its total to 392.99 million, the authority said.

(Reporting by Eve Wu and Kevin Yao; Editing by Christopher Cushing) ((kevin.yao@thomsonreuters.com; +8610 5669 2128;))