These outlets are believed to have linkage with Thanh Nga Supply Foods in Hanoi’s Hai Ba Trung District where at least 21 Covid-19 cases have been confirmed, said a spokesperson for VinCommerce that operates the retail chain.

Sixteen outlets are located in Hanoi, and seven in Ecopark, Hung Yen Province, which is about 40 minutes to the southeast of downtown Hanoi.

VinCommerce denied rumors that "hundreds" of its outlets are linked to the supplier.

Authorities are in the process of disinfecting the outlets and trace contact history of VinMart staff to prevent the spread of the novel coronavirus.

The outlets will only be opened when authorities deem safe, the spokesperson for VinCommerce said.

VinMart is the biggest retail chain in Hanoi with nearly 1,000 outlets.

Hanoi has recorded 1,457 Covid-19 cases in the ongoing wave. The city is on its 10th day of a 15-day strict social distancing campaign.