Radiation levels at nuclear plant now harmful government says

Radiation from Japan's quake-stricken Fukushima Daiichi nuclear plant has reached harmful levels the government says.

The warning comes after the plant was rocked by a third blast which appears to have damaged one of the reactors' containment systems for the first time.

If it is breached there are fears of more serious radioactive leaks.

Chris Hogg reports from Tokyo.