A powerful earthquake, followed by numerous aftershocks, shook southern Japan Sunday morning. Hundreds of people were injured.

The magnitude 7 quake was felt as far away as South Korea. In southern Japan, it damaged homes, shattered windows in high-rise office buildings and toppled walls and stone statues.

At a kindergarten, a recital by students was getting underway when the quake struck. The tremor swayed the room, and mothers ran to calm their panicked children.

Officials say electrical power, gas and water services have been disrupted in many cities on Japan's main southern island of Kyushu.

Japan's Meteorological Agency says the quake was centered in the Sea of Japan, about 70 kilometers off the coast of Kyushu. Seismologists at the agency say this is the strongest quake to hit Kyushu in nearly 18 years.

Officials say the quake is remarkable in that it was extremely shallow, just nine kilometers below the sea surface.

In Fukuoka City, where 1.3 million people reside, roads and sidewalks cracked or swelled. Passenger rail service in many communities was suspended. Airports in Fukuoka and Nagasaki halted flights for a short period, but reopened after inspections revealed no damage to runways.

However, damage is extensive on the tiny island of Genkai at the mouth of Fukuoka Bay. Local government officials requested military helicopters be dispatched to the island to take the injured to hospitals.

Both the prime minister's office and the National Police Agency have established crisis centers to gather information and coordinate relief efforts.

Japan Meteorological Agency official Masahiro Yamamoto is warning of powerful aftershocks. Mr. Yamamoto says tremors of magnitude 6 are possible. There is concern that further aftershocks could also trigger landslides.

Authorities are advising people in southern Japan to stay away from the seacoast. The meteorological agency initially issued a tsunami warning, but it was canceled about an hour after the first tremor.