Japanese Prime Minister Naoto Kan has said his government is in a state of maximum alert over the crippled Fukushima nuclear plant.

日本首相菅直人称，其政府对福岛核电站保持着最高的警戒状态。

Japan is in for the long haul in coping with nuclear fallout from the 11 March earthquake
Plutonium was detected in soil at the facility and highly radioactive water had leaked from a reactor¹ building.

Officials in China, South Korea and the United States have recorded traces of radioactive material in the air.

Earlier, Japan's government strongly criticised the plant's operator, Tepco, over mistaken radiation readings.

Mr Kan told parliament the situation "continues to be unpredictable".

The government "will tackle the problem while in a state of maximum alert," he said.

'Very grave'

Speaking on Tuesday about how the government might fund relief and recovery efforts, Mr Kan said: "We need to pursue various possibilities."

Scrapping²（解体，废弃） a planned cut in corporate³ taxes was one option under consideration, he added.

Chief Cabinet Secretary Yukio Edano said: "The situation is very grave."

"We are doing our utmost（极度的） efforts to contain the damage.

"We need to avoid the fuel rods from heating up and drying up. Continuing the cooling is unavoidable... We need to prioritise injecting water," he said.

Correspondents say the government has been accused of indecision（优柔寡断） and delay.