Japan has confirmed eight more cases of the Omicron variant of the coronavirus, the government said Friday, bringing the total number of infections from the new strain in the country to 12.

The government will handle the eight, who have a travel history to the United States, Mozambique, Namibia and the Democratic Republic of the Congo, as having close contact with a total of about 470 people on five flights that arrived in Japan with them from Nov. 28 to Tuesday, according to the health ministry.

The eight, aged between below 10 to in their 60s, landed at either Tokyo's Haneda airport, Narita airport near the capital or Kansai International Airport in Osaka Prefecture, the ministry said.

One of the eight was a man in his 40s who arrived at Kansai airport from Los Angeles last Sunday, making it the first time that an Omicron case has been detected at the western Japan airport.

Of the eight, two people are relatives of the first case of the variant confirmed in Japan -- a Namibian diplomat who arrived from the African country on Nov. 28, according to a government source.

The two family members tested negative when they entered Japan with him, but their test results were positive last Saturday and Wednesday, respectively.

Including the two, all the eight people had no symptoms when they entered Japan.

However, three of them -- men aged in their 40s to 60s with a travel history to Congo -- currently have symptoms such as fever, sore throat and difficulty in breathing.

Seven people had received two doses of vaccines.

The eight were confirmed to be infected at facilities designated by the quarantine offices of the airports.

Commenting on the confirmation of the eight new cases, Deputy Chief Cabinet Secretary Seiji Kihara said, "We will thoroughly implement appropriate anti-virus measures by monitoring the situation through strengthened border control and genome analyses."

Japan announced its first case of the new variant on Nov. 30.

The World Health Organization has warned the Omicron variant, which has been confirmed in many other parts of the world, could be more transmissible than previous strains of the virus or able to evade immunity provided by vaccines.