Officials in Japan are sounding the alarm about the coronavirus as the nation prepares to see off one year and welcome another. Their calls for caution come as more cases of the Omicron variant are confirmed in airports and communities.

Trains and planes are crowded with people returning to their hometowns for the New Year holidays. Tuesday saw many central and local government officials wrap up their work for the year. But Tokyo Governor Koike Yuriko says now is not the time to get complacent.

She said," We must be aware that community infections of the Omicron variant could occur at an accelerated pace due to people's movements during the holiday. An explosive spread is possible."

Community transmission of the variant has been detected in 7 prefectures. They include the capital and Okinawa. The first cluster infection was confirmed on Tuesday in Osaka at a care facility for elders. Experts warn a rapid spread could put the medical system under strain, despite global reports suggesting the variant may be less prone to causing severe symptoms.

The government is currently rolling out booster vaccines to medical workers. Elderly people are the next priority group. Officials plan to allow for a shorter minimum period between the second and third shots than the current 7 months.

Authorities across Japan confirmed 385 new coronavirus infections on Tuesday. A record 69 were at airport quarantine facilities. The seven-day average through Monday is 51 percent higher than the previous week.