Tokyo, Dec 1 (IANS): Japan confirmed its second case of the Omicron variant of the Covid-19 on Wednesday, the top government spokesman said.

A man in his 20s who arrived from Peru at Narita airport near Tokyo on Saturday was confirmed as infected with the Omicron variant, Chief Cabinet Secretary Hirokazu Matsuno said.

The non-Japanese man from Peru is currently in quarantine at a medical facility, and was not in close contact with the first case, who is a diplomat in his 30s travelling from Namibia, according to the government.

Scientists are seeking to figure out whether the new strain is more transmissible or able to evade vaccine-induced immunity, Xinhua news agency reported.

Earlier on the day, Matsuno said Japan will deny re-entry to all foreigners who have recently been to Angola, Botswana, Eswatini, Lesotho, Malawi, Mozambique, Namibia, South Africa, Zambia and Zimbabwe.

The measure will come into effect Thursday and remain in place "for the time being," Matsuno told a press conference. Japan has already banned new entries of foreigners from around the world from Tuesday.

Exemptions are allowed to be made in "special circumstances" involving foreign spouses and children of Japanese citizens, diplomats and humanitarian cases, the government has said. But eligibility for such exemptions is being narrowed as part of efforts to keep out the Omicron variant, Matsuno said.

The transportation ministry also said Wednesday that it has demanded that airlines stop accepting new reservations for international flights arriving in Japan as part of tighter border controls.

The World Health Organisation (WHO) has designated the Omicron strain a "variant of concern," warning it may be highly transmissible or able to evade immunity gained from vaccines or previous infections.