At least four people have been killed and about 60 hurt by a 7.2-magnitude earthquake which struck the north of Japan's main island.

The epicentre was in Akita prefecture, 100km (60 miles) north of the city of Sendai, at a depth of 10km (6.2 miles), according to the US Geological Survey.

The tremor rattled buildings in nearby towns and in the capital, Tokyo, 390km (240 miles) to the south.

All high-speed bullet trains in the area were automatically shut down.

Several gallons of radioactive water leaked from two pools storing spent fuel at the Fukushima nuclear plant, but the operator said this posed no risk to the environment.

Two other nuclear power plants in the area were being inspected but there were no immediate signs of damage, officials said.

Several people were reportedly buried under mud at a hot spring hit by a landslide, with up to 100 more reportedly trapped.

Advance warning

Seismologists had issued advance warning of the earthquake moments before it struck around 0845 (2343 GMT on Friday).

Footage from NHK television showed surveillance cameras in Sendai being shaken violently for about 30 seconds.

Chief Cabinet Secretary Nobutaka Machimura told reporters in Tokyo that one person had been killed by a landslide triggered by the earthquake in Iwaki City in Fukushima prefecture.

Another death occurred in Iwate prefecture, close to the epicentre, when someone ran out of a building in panic and was hit by a lorry.

A third victim was a construction worker hit by a rock at a dam in Iwate, according to the National Police Agency.

A fourth body is reported to have been found in the mountains.

Four people were badly injured near the airport in Sendai when a bus in which they were travelling was jolted by the tremors, Japanese television reported.

Children and at least one teacher were also reportedly hurt when window panes broke at a child care centre in Oshu, it added.

Japan is one of the world's most earthquake-prone countries and experiences thousands of minor tremors each year.

An earthquake last year in central Japan caused a small radioactive leak from the Kashiwazaki-Kariwa nuclear plant.

BBC News