The government placed three prefectures under a quasi-state of emergency on Sunday in response to a surge in COVID-19 infections that local governors say are linked to the spread of the omicron variant at U.S. military bases.

The quasi-emergency measures will be effective until Jan. 31 in Okinawa and parts of Yamaguchi and Hiroshima, allowing prefectural governments to strengthen their anti-coronavirus steps and request that dining establishments shorten their business hours and stop serving alcohol.

The measure, the first under Prime Minister Fumio Kishida, who took office in October, comes at a time when medical experts warn of a sixth wave of infections in the country and a renewed strain on the medical system.