A strong earthquake with a preliminary magnitude of 7.2 struck off the coast of northeast Japan on Wednesday, the Japanese Meteorological Agency (JMA) said, but there were no reports of damage or injuries.

A tsunami advisory of up to 50 cm was issued for northeastern Japan after the quake, which occurred at around 11:45 a.m. (0245 GMT), the JMA said, and a 60 cm wave reached Ofunato port, about 450 km from Tokyo, Kyodo news agency said.

'First I felt a jolt that pushed from underneath, then a big sideways tremor that lasted for about 20 seconds,' Yoshiyuki Sato, an official at Kurihara City in Miyagi prefecture, about 300 km (186 miles) northeast of Tokyo, told Reuters.

'The tremor was relatively big but things did not fall off the shelves in the city government building,' he said.

The focus of the tremor was 10 km below the seabed off the coast of Aomori prefecture, public broadcaster NHK said.

The regional utility, Tohoku Electric Power, said its Onagawa nuclear plant was operating normally after the quake. Tokyo Electric Power Co Inc also said there was no impact on its power plants in the region.

Bullet trains resumed running in northeastern Japan after stopping briefly, Kyodo reported.

Japan's northeast Pacific coast, called Sanriku, has suffered from quakes and tsunamis in the past. In 1933, a magnitude 8.1 quake in the area killed over 3,000 people, and last year fishing facilities were damaged after by tsunami caused by a strong tremor in Chile.

Earthquakes are common in Japan, one of the world's most seismically active areas. The country accounts for about 20 percent of the world's earthquakes of magnitude 6 or greater.-Reuters