Ningbo in East China's Zhejiang province has reported 16 new confirmed COVID-19 cases amid the latest resurgence of the virus, according to local authorities on Monday.

The city recorded the first confirmed case in Beilun district on Saturday morning and the district upgraded its emergency response to the COVID-19 to the highest level on Saturday afternoon.

A temporary closure in the district began and closed-loop management was imposed on Yanhai village, a factory and dormitories of Shenzhou International Group, where the case lived and worked, on the same day. These places were identified as medium-risk areas for COVID-19.

Mass nucleic acid tests for all residents in Beilun district were also launched.

As of Sunday, 15 locally transmitted COVID-19 cases have been detected during the mass nucleic acid tests.

Sun Liming, deputy director of the Zhejiang Provincial Health Commission said at a news conference on Sunday that the outbreak in Beilun district was not related to the recent outbreak in Hangzhou, Shaoxing and Ningbo's Zhenhai district. The Beilun virus strain, upon checks and analysis, is the same one as an evolutionary branch of Delta variant AY.57, which raged in Vietnam recently.

"The first patient was discovered during a routine nucleic acid test before he was admitted to the hospital for treatment while others were all identified during the mass nucleic acid tests conducted at the areas under closed-loop management," Sun noted.

According to Sun, no locally transmitted COVID-19 cases were found in the province except Shenzhou International Group.

Many hospitals and clinics in Beilun have shut down and public transportation has also been suspended.

To ensure container services and ship operations of port areas in Beilun, part of Ningbo Zhoushan Port, a transportation green channel opened for container trucks under strict COVID-19 prevention and control measures.

Yu Yin in Ningbo contributed to the story