Japan earthquake live: Tsunami warning after huge quake - with 'hazardous' waves expected to hit Japan and Russia

Speaking at the ongoing news conference in Tokyo, the Japan Meteorological Agency says the first parts of the country have already been hit by a tsunami.

"Some areas have already received their tsunami," the official says.

He adds that other areas are expected to be hit around 1am-2am local time - anytime now, really.

For those at risk, people are being told to evacuate to higher ground and avoid coastal areas.

The biggest recorded waves so far are around half a metre, the official says, but early warnings cautioned they could get as big as three metres.

Officials from the Japan Meteorological Agency in Tokyo are holding a news conference to update the country on the latest after an earthquake struck in the last few hours.

Watch live in the stream at the top of the page and we'll bring you any key updates here.

Earthquake tremors impacted the Kyodo News newsroom this afternoon. 

Bookshelves were knocked over and documents were left scattered across the floor at the bureau in Hakodate.

We've just received an update on the earthquake's effect on Japan's electricity facilities.

Utility companies Tohoku Electric Power and Hokkaido Electric Power said no irregularities have been reported at their nuclear power plants in the region. 

But according to Tohoku Electric, thousands are currently without power.

Senior lecturer in oceanography at the University of Southampton Simon Boxall tells Paste BN that today's earthquake is "in the same location" as the 2011 earthquake that killed more than 19,700 people and sparked a disaster at the Fukushima nuclear plant.

Speaking to presenter Jayne Secker, Boxall says that in the coming minutes and hours we'll find out just how damaging today's earthquake is.

But he adds that "not all quakes create tsunamis".

Watch the interview below...

The Japanese PM's office says she has three instructions to the government regarding its response to the earthquake.

They are:

1. Provide timely and accurate information to the public about the earthquake, tsunami, any evacuations and more.
2. Assess any damage caused by the earthquake as soon as possible.
3. Act closely with local governments and prioritise human life in all efforts.

The Japanese prime minister, Sanae Takaichi, has provided brief comments on the situation to reporters just a few moments ago.

She said the government set up an emergency task force to assess the extent of damage. 

"We are putting people's lives first and doing everything we can," Takaichi said.

First reports of damages are coming through.

According to public broadcaster NHK, several people were injured at a hotel in the town of Hachinohe in the northeastern prefecture of Aomori.

Previously, the Japanese Meteorological Agency said a tsunami of 40cm had been observed at the ports of Mutsu Ogawara in the Aomori prefecture and Urakawa on the island of Hokkaido.

The Japan Meteorological Agency has issued a tsunami warning, as we explained in our post at 15.09.

According to the JMA, this means that people in affected areas should adhere to the following advice:

• Evacuate from coastal or river areas immediately to "safer places";
• High ground or a tsunami evacuation building would be seen "safer places"; 
• Do not assume you are in a safe place as tsunami heights may exceed estimates due to coastal topography and over factors. Keep evacuating to higher and higher ground wherever possible;
• Do not leave evacuation areas until the tsunami warning has been cleared, as waves may hit repeatedly.　

The Japanese Meteorological Agency has issued an alert for tsunami waves up to three metres in height in the prefectures of Hokkaido, Aomori and Iwate.

Images are coming through showing tsunami warnings displayed on televisions in Japan, with the three-metre height spelt out on screen.