Announcing the decision, municipal People's Committee Chairman Chu Ngoc Anh said Wednesday that certain Covid-19 hotspots in the capital city have been brought under control over the past weeks. Thanh Xuan District is the most high-risk area at the moment, with 10 of its 11 wards recording Covid-19 cases. Thanh Xuan Trung Ward has recorded as many as 42 cases, he noted.

To control the spread of the virus in the district's clusters, Anh asked local authorities to strictly monitor locked down areas, erect warning signs and absolutely forbid people from going to others' homes.

"Everyone inside locked down areas must be treated as a close contact of Covid-19 cases and must be tested. Whoever refuses to do will be taken into centralized quarantine camps," he said.

Khong Minh Tuan, deputy director of the Hanoi Center for Disease Control (CDC), proposed testing every vendor at the Nga Tu So night market for risk assessment, as potential infection sources might lurk among them.

The Hanoi Department of Health has requested Thanh Xuan District to strengthen monitoring at Covid-19 checkpoints in certain locked down areas, and collect samples for Covid-19 testing thrice a day.

A representative of the Hanoi police department said not everyone has followed coronavirus control measures properly. Thanh Xuan Trung Ward should increase patrol frequency to once every hour and strictly punish all violations, he added.

Hanoi has recorded 3,005 local Covid-19 cases since the fourth coronavirus wave hit Vietnam in late April.

The capital has undergone a series of social distancing periods, with the latest one being extended until September 6.