A single-day record of 235 COVID-19 cases among U.S. forces in Okinawa Prefecture were confirmed Saturday, local officials said, following a cluster infection that broke out last month at one of the U.S. bases there.

It was not clear whether any of the cases were of the highly transmissible omicron variant, and the breakdown of U.S. bases affected was also not known. The cumulative number of COVID-19 cases related to the U.S. military has now reached 3,613.

Japan's border control measures have come under scrutiny in the wake of a group infection at the U.S. Marine Corps' Camp Hansen in the southern island prefecture, which hosts the bulk of the U.S. military facilities in the country.