Health Minister Nguyen Thanh Long revealed the information at a meeting Wednesday, 10 days after he died.

The strain, known as CAL.20C, originated from a group of viruses tracked from Europe to New York early in the pandemic and was first detected in California in July. The virus strain has been spreading fast in many U.S. states and has mainly surfaced in South Korea, Taiwan and India.

The 54-year-old Japanese man who entered Vietnam on Jan. 17 was quarantined at a hotel in Ho Chi Minh City and showed two negative test results. He later took a flight to Hanoi and underwent self-quarantine at Somerset West Point on Feb. 1.

On Feb. 13, he was found dead inside his hotel room, with his sample tests returning positive for the novel coronavirus.

Two other people in close contact with him were confirmed positive as well.

Vietnam has earlier reported U.K. coronavirus variant in the outbreak in Hai Duong and neighboring Quang Ninh, and the South African variant on an imported case.

Recently a patient in Hai Duong was also found to be infected with the highly contagious coronavirus variant from South Africa.

Long said: "Pathogens could exist in the community, and especially spread by foreign experts and migrants."

In light of new variants, the government has limited inbound flights. Only special cases approved by authorities can enter the country.

Vietnam has closed its borders but allows a limited number of flights to return citizens from overseas or carry foreign experts, with all arrivals required to enter 14-day quarantine.