Of the 49, two were in Ho Chi Minh City, a man and a woman aged 26 and 46 and living in District 12.

The man is a baggage handler at the city's Tan Son Nhat International Airport, while the woman was already isolated after being designated an F1 for being in contact with an infected person.

The remaining 47 local cases were found in the northern province of Hai Duong, the epicenter of the current outbreak. Of them 43 were in quarantine as F1 and the remaining four live in areas already locked down.

Four people were diagnosed with Covid-19 while entering Vietnam - an American expert, a Vietnamese returnee from the U.S. and a Taiwanese and South Korean woman each.

They had been sent to quarantine upon landing in HCMC, and are currently being treated at the Cu Chi District field hospital.

With the latest additions, the number of cases in the latest outbreak which began on January 28 has risen to 604 in 13 cities and provinces.

Hai Duong accounts for 430, followed by Quang Ninh (59), HCMC (36), Hanoi (30), Gia Lai (27), Binh Duong (six), Bac Ninh (five), Dien Bien (three), Hoa Binh, Hung Yen and Bac Giang two each, and Hai Phong and Ha Giang one each.

Deputy Prime Minister Vu Duc Dam, who heads the coronavirus task force, said on Saturday afternoon that the Covid-19 situation in Vietnam is "basically under control" and good Tet celebrations have been ensured.

All the new cases had been found in quarantine or locked-down areas, and so the risk of spread is low, he added.

The Ministry of Health said the U.K. variant is responsible for the outbreak in northern Vietnam and a variant from Rwanda caused the outbreak at HCMC's Tan Son Nhat airport.

Hanoi Vice Chairman Chu Xuan Dung announced on Saturday that people returning to the capital after Tet have to make health declarations.

He said industrial zones need particular attention since a large number of workers would return after the holiday.

Dung instructed the Department of Education and Training to decide by next Tuesday whether students could return to school after Tet or take online classes.

The national Covid tally stands at 2,195 now with 35 deaths.