Infections with the Omicron variant of the coronavirus have been reported across 22 out of 47 prefectures in Japan, a tally based on local government reports showed Thursday, one month after the first domestic case was confirmed.
Around 500 people have been infected with the highly transmissible strain in the country, according to the reports. The development has fueled concern about a potential resurgence of COVID-19 infections during and after the year-end and New Year's holiday period and its impact on the medical system.
Most of the Omicron cases have been detected in quarantine. But community spread of the variant has also been reported in urban areas, including Tokyo and Osaka.
Prime Minister Fumio Kishida called on the public the same day to take extra precautions to prevent the spread of the coronavirus as people start traveling across Japan for the holiday period.
"As the community spread of the Omicron variant has been confirmed, I have to ask you to be more cautious than usual to prevent a resurgence of infections," Kishida said in a video posted on the Twitter account of the Prime Minister's Office.
He asked people to consider cautiously whether to return to their hometowns during the period. In case of traveling, he called for taking thorough measures such as wearing masks, washing hands and avoiding the "three Cs" -- closed spaces, crowds and close-contact settings.
As for those holding parties, Kishida asked them to do so in small groups and at eateries with certificates for taking anti-virus measures.
Daily coronavirus cases in Japan have been declining since hitting a peak of over 25,000 this past summer, with more than 75 percent of the population inoculated with two vaccine shots.
But concern remains over a possible resurgence during winter. On Wednesday, the nationwide tally stood at 502 cases, exceeding 500 for the first time in over two months.
For international travel, the Japanese government implemented strict border controls on Nov. 30, banning the entry of nonresident foreign nationals and toughening quarantine measures for Japanese citizens and foreign residents who have recently been to certain countries or regions.
Kishida has said he will decide whether to relax the border enforcement measures in line with the infection situation in the year-end and New Year period.