Story highlights Thirty-nine people are injured, seven of them seriously, police say

The quake destroys homes in a popular ski resort in Nagano prefecture

No electric facilities were damaged, power company says

Quake reported at 6.8 magnitude by Japanese agency; USGS says it was 6.2

A strong earthquake shook central Japan on Saturday night, injuring dozens of people and destroying homes in a well-known ski resort, authorities said.

Reports differed on the intensity of the quake, centered in a remote mountainous area of Nagano prefecture. The Japan Meteorological Agency reported it was magnitude 6.8; the U.S. Geological Survey (USGS) said it was magnitude 6.2.

One of the hardest hit areas was the skiing village of Hakuba, where at least seven housing and storage structures collapsed.

Seven of the 39 people hurt in the quake suffered serious injuries, Nagano prefectural police said.

Japanese television stations carried images of landslides that had cut off roads and railroads, as well as flattened houses and warped highways.

More than 300 rescue workers were deployed to search for people trapped in collapsed homes. Authorities said the rescue operation was completed.

No electric facilities, including nuclear power plants, were damaged, the Tokyo Electric Power Co. said via Twitter Saturday.

Aftershocks followed the main quake Saturday night, including one measured at magnitude 4.1, the Japan Meteorological Agency said.