Liaoning reported four confirmed Covid-19 cases between 12am and 7pm on Saturday, with one reported in the provincial capital Shenyang and three others in the city of Yingkou, said the provincial health commission.
A total of five asymptomatic carriers were also reported in Yingkou on Saturday, the local health commission added.
As of Saturday, nine residential communities and villages in Yingkou had been upgraded to medium-risk areas for Covid-19.
Mainland China reported 18 new Covid-19 cases on May 15, up from 14 cases a day earlier, the country's national health authority said on Sunday.
The National Health Commission (NHC) said in its daily bulletin that 4 of the new cases were local infections, all in China's northeastern Liaoning province. The rest originated overseas.
On Friday, the NHC reported China's first local transmissions in over 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 recorded at 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. - Xinhua