Japanese authorities have issued a tsunami warning and told people to evacuate after an earthquake off the country's northeastern coast.
A tsunami wave of three metres (10ft) is expected to hit after a 7.5-magnitude quake was recorded at 4.53pm local time (7.53am UK time).
Japanese media has reported that tsunamis will also be expected over the next hour in Aomori, Miyagi and Fukushima, though these waves are only expected to be three ft tall.
An 80cm (31-inch) tsunami wave has already hit a port in northern Japan.
The wave was observed at 8.34am GMT) at a port in Kuji, Iwate, according to Japan's Meteorological Agency (JMA) . It previously said a 70-centimetre wave had struck at 5:32 pm.
The earthquake's epicentre was in the Pacific Ocean, and was six miles deep.
The JMA warned those near water to get to safety: 'Evacuate immediately from coastal regions and riverside areas to a safer place such as high ground or an evacuation building.
'Tsunami waves are expected to hit repeatedly. Do not leave safe ground until the warning is lifted.'
The tremor was strong enough to shake large buildings as far as Tokyo, hundreds of miles away, while aerial footage showed huge waves dominating the shorelines of Japan.
Japan's PM warned that her office has 'received a report that "human and material damage" is currently being confirmed', though did not detail the extent of destruction.
Massive waves were seen consuming vast swathes of Japan's coastline
Japanese soldiers have been sent to help affected areas, with several seen in the Iwate prefecture
Footage taken from inside a cafe in Japan showed signs and hanging lights swaying side to side.
Another clip showed the light from an ornate chandelier rapidly flashing while the ornamental piece of lighting swayed.
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.
Officials from the Tokyo Electric Power Company said that there are so far no changes in radiation from the Fukushima power plants
They added that no abnormalities have been detected at its Higashidori nuclear power plant in Aomori prefecture or its Onagawa plant in Miyagi prefecture.
A recyclable-fuel storage company also said no abnormalities were seen at the interim storage facility for spent nuclear fuel in Aomori prefecture.
The prime minister's office has said that it has set up a crisis management team in the wake of the earthquake.
She said at a press conference: 'For those of you who live in areas for which the warnings have been issued, please evacuate to higher, safer places such as higher ground.'
Japanese soldiers have been sent to help affected areas, with several seen in the Iwate prefecture.
The US' National Weather Service said following the quake that a tsunami is not expected to hit California, Alaska, Washington or Oregon in America, nor will anything hit British Columbia in Canada.
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 percent 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.
In 2024, the JMA issued its first special advisory of a possible 'megaquake' along the Nankai Trough.
This nearly 500-mile-long undersea trench is where the Philippine Sea oceanic tectonic plate is 'subducting' - or slowly slipping - underneath the continental plate that Japan sits atop.
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' (Pictured: Japan's coastline following the quake)
Japan accounts for 18% of the world's earthquakes (Pictured: A Japanese coastline being hit with major waves)
The government has said a quake in the Nankai Trough and subsequent tsunami could kill as many as 298,000 people and cause up to $2 trillion in damage.
The JMA lifted the 2024 advisory after a week but it led to panic-buying of staples like rice and prompted holidaymakers to cancel hotel reservations.
It issued a week-long second 'megaquake' advisory in December 2025 after a magnitude-7.5 tremor struck off the northern coast.
The December 8 quake triggered tsunami waves of up to 28 inches and injured more than 40 people, but no major damage was reported.