An earthquake with a preliminary magnitude of 6.5 struck southeast Hokkaido late Saturday, causing blackouts and prompting highway closures in some areas, the Meteorological Agency and local officials said.

The focus of the quake, which struck at 11:17 p.m. at a depth of about 108 km, was in the mountainous Tokachi region about 15 km southwest of Obihiro.

There were no reports of serious damage or problems at the three nuclear power facilities in the region, and only about a dozen people sustained injuries, most of them minor, they said.