An 8.8 magnitude earthquake hit Japan's northeastern Honshu island Friday, said the Japan Meteorological Agency, and a huge tsunami warning was issued.

The agency revised the magnitude of the quake from 7.9 and the U.S. Geological Survey upgraded it to magnitude 8.9.

The focus of the quake, which occurred at 2:46 p.m., (0546 GMT), was located some 10 km under the sea 130 km east of the Miyagi Prefecture, said the agency.

Violent tremors were felt in areas along Japan's Pacific coast, including Tokyo and Osaka.

After the major quake occurred, all cabinet ministers were summoned to the prime minister's office and a crisis management team were set up there.

Chief Cabinet Secretary Yukio Edano said the government has dispatched Self-Defense Force troops to Miyagi Prefecture. And the defense ministry sent eight air fighters to check damage in the worst-hit areas.

All Shinkansen bullet trains were halted, local media reported, citing JR East.

And Tokyo metropolitan expressways as well as Tokyo subways and suburban rail services were also closed following the quake. But no big collapses were reported in Tokyo expressways.

In Miyagi Prefecture, Sendai airport was closed. A major power outage and gas leaks were reported in a number of areas in Sendai city, capital of the prefecture.

Meanwhile, Numerous people were injured, local media reported, citing Miyagi prefecture police.

In Iwate Prefecture, a 4-meter-high tsunami was observed and dozens of cars and buildings were washed away.

In Fukushima Prefecture, two nuclear plants on Pacific coast were automatically shut down.

Fires were reported across a wide area, including at an ironworks in Chiba Prefecture.

The quake affected the nation's key transportation systems, including Narita airport, which were closed for safety checks of its runways.