A strong earthquake measuring a lower 6 on the Japanese scale of 7 struck Shizukuishi, Iwate Prefecture, at 4:58 p.m. Thursday, the Meteorological Agency said.

No tsunami warning was issued.

At least seven people were slightly injured, including two junior high school students who were hurt when ceiling light covers fell on their heads at a public leisure facility, according to police. Although the extent of the damage has not been confirmed, a high-voltage electric wire was found snapped, police said.

The Iwate Prefectural Government immediately set up emergency disaster headquarters. The agency issued a warning at 5:15 p.m. for local residents to be on alert for volcanic activity at Mount Iwate. The quake centered in the area of Shizukuishi, about 15 km from the mountain.

The area around the 2,039-meter mountain has been experiencing seismic activity since earlier this year. The Self-Defense Forces dispatched helicopters to Shizukuishi and its vicinity, but crews reported no visible damage to structures in the area.

Iwate Prefectural Police also requested their counterparts in Aomori, Miyagi, Yamagata and Fukushima prefectures to mobilize helicopters and scope out any damage in Iwate, officials said.

The quake measured 4 on the Japanese scale in other parts of Shizukuishi and 3 in Morioka, Mizusawa, both in Iwate Prefecture, as well as Kakunodate in neighboring Akita Prefecture.

The temblor's focus was near the surface in the northern part of Iwate Prefecture, the agency said.

According to Iwate police, seven or eight vehicles were stranded on a prefectural highway that was hit in more than 10 spots by landslides on Mount Iwate's southern slope.

Part of a road near Gembu spa in Shizukuishi buckled, preventing the passage of buses. Nearby, 23 homes suffered power outages when a high-voltage wire snapped, they said.