TOKYO (REUTERS) - Japan recorded a surge in new coronavirus cases on Wednesday (Jan 12), with infections reaching four-month highs in the major metropolitan areas of Tokyo and Osaka as the Omicron variant spreads.

New cases totalled 2,198 in the capital of Tokyo, while the western prefecture of Osaka recorded 1,711, nearly tripling from the day before. Those marked the highest levels since early September.

Covid-19 cases across Japan will exceed 10,000 on Wednesday, according to a tally by broadcaster TBS.

That tally would be the highest number of infections in Japan in a single day since Sept 9.

"We must brace for the rapid spread of infections to continue," Chief Cabinet secretary Hirokazu Matsuno told reporters, noting that the Omicron variant had been discovered in most regions of the country.

On Sunday, Japan stepped up coronavirus restrictions in three regions that host US military facilities, after it appeared that Omicron outbreaks at the bases spilled into the surrounding communities.

Prime Minister Fumio Kishida said on Tuesday that Japan will maintain strict border restrictions through February to slow the spread of Omicron.