Genome sequencing has revealed that all locally transmitted confirmed cases of COVID-19 in the recent outbreak in Manzhouli, Inner Mongolia autonomous region, involved the Delta variant, local officials said at a news conference on Saturday.

The virus was either imported by a person or with goods, said Ma Qiang, Party secretary of Manzhouli.

Inner Mongolia logged 28 new local cases and two asymptomatic carriers on Sunday, the regional health commission said on Monday.

Of those, 27 confirmed cases and two asymptomatic carriers were found in Manzhouli, a border city under the jurisdiction of Hulunbuir.

"The city has provided services for those needing special care, including the elderly, young children, the disabled and hospital patients," said Guo Haitao, deputy director of the city's commerce bureau. "Staff members will inquire and record the daily necessities and drugs urgently needed as they visit people's homes for daily testing."

The local government also coordinated with medical institutions in other cities — such as Beijing, Tianjin and Harbin — to provide online medical services to resolve difficulties in the medical treatment of residents who are under home-quarantine.

The city started a ninth round of nucleic acid testing at 8 am on Monday.

As of Sunday, the region had reported 360 locally transmitted confirmed cases and two asymptomatic carriers since three residents in Manzhouli tested positive for the virus on Nov 27.

The region's neighbor, Heilongjiang province, reported seven local cases on Sunday, all of which were detected in Harbin, the provincial health commission said on Monday.

All the cases were related to a confirmed case reported previously in Manzhouli, the local government reported. In a statement released on Saturday, it urged residents not to leave the downtown area of the city.

"Those who have to leave for special reasons should provide negative nucleic acid test results twice within 48 hours and follow good health practices," the statement said. "Permission from a competent organization or the community, as well as the local epidemic prevention and control headquarters, are also required."

All kindergartens, primary schools, middle schools and vocational schools will continue online courses, the local education bureau said on Sunday.