SIRENS wailed along a devastated coastline to mark exactly one week since an earthquake and tsunami triggered a nuclear emergency, and the government acknowledged it was slow to respond to the disasters that the prime minister called a “great test for the Japanese people.”

The Japanese government says it was overwhelmed by the scale of to the huge earthquake and tsunami, slowing the response to the nuclear crisis.

Japan’s nuclear safety agency has raised the severity rating of the country’s nuclear crisis from Level 4 to Level 5, putting it on par with the Three Mile Island accident in the US in 1979.