TOKYO - A 7.9-magnitude earthquake has struck off Japan's northeastern coast, shaking buildings in Tokyo for several minutes and sending people out into the streets.

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Japan's meteorological agency warns that a tsunami as high as 20 feet (6 meters) could strike the coast near Miyagi prefecture, closest to the epicenter.

The agency says the quake struck at 2:46 pm Friday at a depth of 6 miles (10 kilometers), about 80 miles (125 kilometers) off the eastern coast.

Several quakes had hit the same region in recent days, including a 7.3 magnitude one on Wednesday.