Sporadic COVID-19 cases are continuing to emerge in more parts of China, with Ningbo, in East China's Zhejiang province, reporting three COVID-19 cases on Monday as the city launched stringent measures to fight the pandemic.

The three cases, all members of one family in Ningbo's Zhenhai district, have been sent to a designated hospital for treatment. Schools in the district were closed on Monday, the local authorities said, and all flights from Ningbo to Beijing were canceled due to pandemic prevention measures.

On Monday morning, the city imposed complete closed-off management on the residential community and businesses in Zhenhai's Jiaochuan subdistrict, where the three infected patients lived and worked.

All residents and workers in the area began receiving nucleic acid tests on Monday morning. A medical worker at the nucleic acid testing site in the community said 120 medical personnel arrived at the test site at 4 am on Monday to conduct nucleic acid tests on residents.

Most hospitals in the district suspended offline outpatient services due to COVID-19 prevention measures from Monday and two rounds of nucleic acid tests will be conducted on all medical personnel at three hospitals in Zhenhai.

The local authorities said public places in Zhenhai, such as scenic spots, performance venues, internet cafes and stadiums, had been closed and cultural, tourism and sports activities have been called off.

The Chinese mainland recorded 38 new locally transmitted COVID-19 cases on Sunday, the National Health Commission said in its daily report on Monday.

Twenty-eight were reported in the Inner Mongolia autonomous region, seven in Heilongjiang province, two in Yunnan province and one in Hebei province.

In Inner Mongolia, 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 Manzhouli'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 has also coordinated with medical institutions in other cities－such as Beijing, Tianjin and Harbin, Heilongjiang's provincial capital－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 seven local cases reported in Heilongjiang on Sunday were all detected in Harbin, the provincial health commission said on Monday.

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

"Those who have to leave for special reasons should provide negative nucleic acid test results twice within 48 hours and follow good health practices," it 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 with online courses, the city's education bureau said on Sunday.

Yu Yin contributed to this story.