A 7.4-magnitude earthquake struck northern Japan on Monday, Japan's Meteorological Agency (JMA) said, issuing a tsunami warning for waves up to three metres (10 feet).
The quake hit at 4:53 pm local time in Pacific waters off northern Iwate prefecture and the tremor was strong enough to shake large buildings as far as Tokyo, hundreds of kilometres away.
The earliest tsunami waves could reach the northern shoreline immediately, the weather agency said.
"Evacuate immediately from coastal regions and riverside areas to a safer place such as high ground or an evacuation building," it said, warning that damage due to tsunami waves was expected.
"Tsunami waves are expected to hit repeatedly. Do not leave safe ground until the warning is lifted," it said.
The prime minister's office said it had set up a crisis management team.
Japan is one of the world's most seismically active countries, sitting on top of four major tectonic plates along the western edge of the Pacific "Ring of Fire".
The archipelago, home to around 125 million people, typically experiences around 1,500 jolts every year and accounts for about 18% of the world's earthquakes.
The vast majority are mild, although the damage they cause varies according to their location and the depth below the Earth´s surface at which they strike.
In 2011, a magnitude-9.0 quake triggered a tsunami that left 18,500 people dead or missing and caused a devastating meltdown at the Fukushima nuclear plant.
