Two-phased closed-off management and a new round of nucleic acid testing for residents were launched in Shanghai on Monday morning.

China's financial hub on Sunday reported a record 3,450 asymptomatic COVID-19 cases, accounting for nearly 70 percent of the nationwide total, along with 50 symptomatic cases. The daily new infection numbers hit an all-time high as the city suffered its worst outbreak this month since the start of the pandemic.

"After analyzing the results of the screening carried out in Shanghai over past days, we found that there are regional clusters and sporadic cases across the city. It's necessary to implement more decisive and resolute measures now," said Wu Fan, a member of the expert team leading the Shanghai COVID-19 prevention and control efforts at a briefing held on Monday.

"The new round of testing aims to reduce social mobility, identify infections and eliminate the transmission of the virus in neighborhoods," Wu added.

Phased closed-off management

From 5 a.m. on March 28 to 5 a.m. on April 1, temporary closed-off management will be enforced in regions lying to the east and south of the Huangpu River, including Pudong and its adjacent areas, to carry out nucleic acid testing, according to the city's COVID-19 prevention and control office.

Then from 3 a.m. on April 1 to 3 a.m. on April 5, similar temporary closed-off management and testing will be launched mainly in urban districts west of the Huangpu River.

The office said the measures are being taken to curb the virus spread, protect people's life and health, and achieve the dynamic zero-COVID target as soon as possible.

In areas affected, closed-off management will take place in residential communities and residents will be required to stay indoors, while non-contact delivery of necessities will be allowed.

All enterprises, except those necessary for ensuring the people's daily needs and the city's operation, will run under closed-off management or have their employees work from home.

Services including bus, subway, ferry, taxi and online ride-hailing will be suspended in the areas under closed management, while airports, railways and international passenger and freight operations are operating normally in the city.

(With input from Xinhua)