Japan reported its first community transmission of the omicron variant of the coronavirus in Osaka Prefecture, with three people confirmed to have contracted the virus through unknown routes, the prefecture's governor said Wednesday.

"It is seen to be the first community spread in the country," Osaka Gov. Hirofumi Yoshimura said, at a time when Japan remains on alert over omicron with strict border controls in place.

Health minister Shigeyuki Goto confirmed to reporters that the cases amounted to a community transmission, adding that the government will maintain the current border control measures for the time being to buy time to prepare measures against the variant.