In a rare appearance, Akihito, 77, went on live TV to make his first public comments on the disaster, and said he was praying for the people.

The emperor spoke after technicians were forced to temporarily abandon a quake-crippled nuclear plant.

The 9.0-magnitude quake and tsunami has killed thousands of people. Thousands are missing and at least 10,000 feared dead after the disaster, which flattened swathes of the country's north-east coast.

On Wednesday morning, yet another fire broke out in one of the reactors, while smoke or steam billowed from another part of the plant.

The plant, about 220km (140 miles) north of Tokyo, was rocked by the first in a series of explosions last Saturday.