Japan PM: Nuclear situation 'grave and serious'

Two weeks after the devastating earthquake and tsunami hit Japan, the country's Prime Minister, Naoto Kan, has said the situation at the Fukushima nuclear plant remains 'grave and serious'.

An investigation is under way in Japan to establish the source of a radiation leak at the quake-hit nuclear plant, which left two workers in hospital.

The plant's operator says dangerously high radiation levels recorded in water at one reactor raise the possibility its core has been damaged.