TOKYO, Dec. 9 (Xinhua) -- An earthquake with a preliminary magnitude of 7.6 struck northeastern Japan late Monday night, prompting the suspension of ocean discharge of nuclear-contaminated wastewater from the crippled Fukushima Daiichi Nuclear Power Plant.

No abnormalities have been reported by nuclear plants in Hokkaido or in the northeastern prefectures of Aomori, Miyagi and Fukushima, public broadcaster NHK reported.

Tokyo Electric Power Company (TEPCO) said that the discharge of nuclear-contaminated wastewater from the Fukushima Daiichi Nuclear Power Plant into the ocean was halted at 11:42 p.m. local time following the issuance of a tsunami warning.

In Aomori and Hokkaido, there have been reports of several non-life-threatening injuries. The Aomori prefectural government said that around 2,700 homes were left without power, Kyodo News reported.

The temblor occurred at 11:15 p.m. local time at a depth of 50 km, measuring upper 6 on Japan's seismic scale of 7 in the city of Hachinohe, Aomori Prefecture, triggering a tsunami warning for coastal areas of Aomori, Iwate and Hokkaido prefectures, said the Japan Meteorological Agency (JMA).

The waves are expected to be up to 3 meters high on the Iwate Prefecture coast, the central Pacific coastal areas of Hokkaido and the Pacific coast of Aomori Prefecture, the JMA said, urging people in affected areas to immediately evacuate to higher ground.

Waves of 50 centimeters were observed in the town of Urakawa, Hokkaido, at 12:21 a.m. local time Tuesday and in Kuji Port, Iwate Prefecture, at 12:10 a.m. local time, the JMA added.

According to Japan Railways, Tohoku Shinkansen bullet train services in northeastern Japan have been suspended in both directions between Fukushima Station and Shin-Aomori Station due to the quake.

Chief Cabinet Secretary Minoru Kihara said the government was gathering information on casualties and property damage. The government set up a crisis management office at the Prime Minister's Office in response to the earthquake. ■