Japan struggles to cool N-plant
Emergency crews are still battling to cool overheated nuclear fuel at a stricken nuclear plant a week after the devastating earthquake and tsunami struck Japan.
Japan's nuclear safety agency raised the alert level for the Fukushima crisis, reclassifying the nuclear accident from Level 4 to Level 5 on a seven-level international scale.
A Level 4 incident is defined as having local consequences and a Level 5 as having wider consequences. The 1986 Chernobyl disaster was rated as 7.
Military fire trucks sprayed the reactor units for a second day, with tons of water arcing over the facility in desperate attempts to prevent the fuel from overheating and emitting dangerous levels of radiation.
"I think they are racing against the clock," Yukiya Amano, the head of the UN's International Atomic Energy Agency said of the efforts to cool the complex, after arriving in Tokyo.
Sirens wailed along the devastated coastline to mark exactly one week since the twin disasters. The government admitted it was slow to respond to the disasters that the prime minister called a "great test for the Japanese people".
The admission came as Japan welcomed US help in stabilising its overheated, radiation-leaking nuclear complex. Nuclear experts have been saying for days that Japan was underplaying the severity of the problems at the Fukushima Dai-ichi power plant.
Prime Minister Naoto Kan vowed that the disasters would not defeat his country.
"We will rebuild Japan from scratch," he said in a nationally televised address, comparing the work with the country's emergence as a global power from the wreckage of the Second World War.
"In our history, this small island nation has made miraculous economic growth thanks to the efforts of all Japanese citizens. That is how Japan was built," he said.