The new patients were recorded in four northern localities of Hanoi and provinces of Bac Giang, Bac Ninh and Lang Son, all linked to previously confirmed patients.

Bac Giang Province recorded 10 cases who are related to Covid-19 patients confirmed at the Van Trung Industrial Park in Viet Yen District.

Bac Ninh Province registered six cases linked to previously confirmed patients at the cluster in Thuan Thanh District.

Hanoi got five cases, including one linked to a group of Chinese experts who flouted their self quarantine protocols in Vietnam last month, and another linked to the director of a state-owned construction firm who allegedly failed to declare his travel history to coronavirus hotspot Da Nang. The city's National Hospital for Tropical Diseases recorded one case and the K Hospital that treats cancer in the capital three. Both hospitals have been locked down for around one week after becoming Covid-19 clusters.

Lang Son Province recorded four cases related to previous infections.

Vietnam's new Covid-19 wave has seen 713 local cases recorded in 26 cities and provinces since April 27.

Of them, 179 are in Hanoi, including 104 cases in the two hospitals under lockdown, 137 in Bac Ninh and 112 in Da Nang.