The foreign ministry had already suspended visa waivers for nine European countries and South Korea.
Visitors from the United States, Europe and Asean countries will be immediately transported to repurposed military camps for 14 days quarantine.
Weeks after Vietnam declared that all 16 of its coronavirus cases had recovered, the number of infected patients is rising once again due to infected people arriving from overseas. So far, no deaths have been reported in Vietnam.
Vietnam has a free trade agreement with Russia and Belarus, while Japan is the second largest source of foreign investment in the country.
The new cases included an American living in southern Ho Chi Minh City, who has travelled to Thailand and returned to Vietnam on a flight from Turkey, and eight Vietnamese people, including four international students returning from Britain, a man returning from France and three people returning from Britain with transit in Dubai.
There are 122 suspected cases being quarantined while nearly 42,000 others being monitored in Vietnam as of Thursday, according to the health ministry. A total of 16 out of the 85 confirmed cases have been discharged from hospital after recovery. - Xinhua/Asian News Network/Agencies