Wuhu, Anhui province, locked down its main urban areas on Sunday — so-called static management — following a report of a COVID-19 infection, the local government said.
Prevention measures include curtailing traffic movement, except for vehicles with traffic permit certificates for epidemic control and prevention purposes, it said.
A hospital reported the infection of a patient on Saturday, according to the city's epidemic control and prevention headquarters in a statement released on Sunday.
Some areas have been strictly quarantined. Residents should not leave home except for a medical emergency, it said.
Mass testing has also been conducted in the city.
The city's three urban districts together reported six asymptomatic infections on Sunday, following the lockdown.
Dozens of infections have been reported since March 23, when a confirmed case from outside the province was found in the city's rural Fanchang district.
Huoqiu county in Lu'an city also imposed static management, starting on Saturday night. Three asymptomatic infections were reported earlier that day.
Regions across the country imposing static management recently include the cities of Kunshan, Zhangjiagang and Taicang in Jiangsu province; Xining, Qinghai province; and Fengdong New Area in Xi'an, Shaanxi province.