Japan's third case of the omicron COVID-19 variant has been confirmed, according to Chief Cabinet Secretary Hirokazu Matsuno, the government's top spokesman. Matsuno said that the case involved a man in his 30s who had a history of staying in Italy, but did not disclose the individual's nationality.

According to government officials, the man arrived at Tokyo's Haneda Airport on December 1. The third omicron case in Japan follows the confirmation of two previous infections during screening at Chiba Prefecture's Narita Airport, which also serves the capital. 

When asked who was in close contact with the man, Matsuno did not answer.

Japan confirms first case of new COVID-19 strain that slipped through net | The Japan Times

All passengers on the same flight were considered close contacts in the previous two cases. As a result of a policy change, all of those close contacts are being monitored and must be quarantined for a total of 14 days. They must also have PCR tests every two days.

Japan closed its borders to foreigners for at least a month on November 30, adopting one of the toughest measures in the world to prevent the spread of Omicron, a variant identified recently in southern Africa and classified as a "variant of concern" by the World Health Organisation.

Prime Minister Fumio Kishida had announced on Monday it would shut its borders to foreigners, but said that "these are temporary, exceptional restrictions that we are implementing for the sake of safety until more information concerning the Omicron variant becomes available."