The tremor had an epicentre in the Pacific Ocean and was 10 km deep, according to ​the Japan Meteorological Agency.

The biggest waves were expected in ​Iwate, Aomori and Hokkaido prefectures, authorities said.

Speaking to reporters, ⁠Prime Minister Sanae Takaichi said the government had set up an emergency ​task force and urged citizens in the affected areas to evacuate to ​safety.

Broadcaster NHK showed ships sailing out of Hachinohe port in Hokkaido in anticipation of the waves, as an alert ‘Tsunami! Evacuate!’ flashed across the screen.

Bullet train services ​in Aomori at the northern tip of Japan’s main Honshu island were ​halted due to the tremors, Kyodo news agency reported.

The quake measured an ‘upper 5’ on ‌Japan’s ⁠seismic intensity scale — strong enough to make it difficult for people to move around.

In many cases, unreinforced concrete-block walls collapse.

Japan is one of the world’s most earthquake-prone countries, with a tremor occurring at least every ​five minutes.

Located in ​the “Ring of ⁠Fire” of volcanoes and oceanic trenches partly encircling the Pacific Basin, Japan accounts for about 20% of the world’s ​earthquakes of magnitude 6.0 or more.

There are no ​nuclear ⁠power plants currently in operation in Hokkaido and Tohoku regions, but Hokkaido Electric Power Co and Tohoku Electric Power Co have several shutdown ⁠nuclear power ​plants there.

Tohoku Electric said it was ​checking the impact of the earthquake and tsunami on its Onagawa nuclear power plant.