A small tsunami triggered by a quake has hit Japan's eastern coast - where the crippled Fukushima nuclear plant is located - but no damage is reported.

The 30cm (1ft) waves reached the region after the 7.1 magnitude tremor struck at a depth of 10km (six miles), about 320km off the coast.

A tsunami alert issued for several areas was later lifted.

Workers at the Fukushima power station had been told to leave waterfront areas for higher ground.

But a Fukushima spokesman later said there was no damage or change in readings at radiation monitoring posts around the plant, according to Reuters news agency.

The Japan Meteorological Agency had warned that a small tsunami - up to one metre (3.3ft) - could reach the eastern coast after the tremor in the Pacific Ocean.

The agency had also issued a "yellow" advisory for Fukushima and the prefectures of Iwate, Miyagi, Ibaraki and parts of Chiba.

But it added: "Though there may be slight sea-level change in coastal regions, no tsunami damage is expected."

The earthquake struck at about 02:10 local time on Saturday (17:10 GMT Friday).

The tsunami advisory was lifted about two hours later.

The Fukushima reactors were damaged by the earthquake and tsunami of March 2011.

Since then, most of Japan's nuclear reactors have remained off, amid impassioned debate over nuclear energy.

More than 18,000 people were left dead or missing in that disaster.