XIAMEN -- Xiamen, a port city in East China's Fujian province, has started a citywide nucleic acid testing due to the latest COVID-19 resurgence in the city, authorities said Tuesday.

All residents in the city should undergo testing, according to the city's COVID-19 prevention and control headquarters.

Colleges, primary and high schools, and vocational schools will have to move their courses online, while kindergartens have been told to suspend operations.

As of 11 am Tuesday, Xiamen had reported 35 locally transmitted confirmed COVID-19 cases and one asymptomatic carrier in the latest resurgence, according to the headquarters.

An area in the city's Tongan district has been classified as high risk after cluster COVID-19 infections were reported in a factory there.

Xiamen residents have been advised not to leave the city unless necessary, and those who want to leave must present a green health code and provide a negative nucleic acid test result within 48 hours before departure.

A citywide nucleic acid testing is also set to start on Tuesday afternoon in Fujian's Putian city. As of Monday, 85 people had tested positive in Putian, consisting of 64 confirmed cases and 21 asymptomatic carriers, said Cai Guoping, deputy head of the city's COVID-19 prevention and control headquarters.

To curb the spread of the virus, Fujian expressway authorities have enforced traffic control at dozens of expressway toll gates across the province.