Workers at the crippled Fukushima nuclear plant in Japan say they have seen steam rising from one of the damaged reactor buildings, for the second time in less than a week.

The company that runs the plant - Tokyo Electric Power Company, also known as Tepco, says it has not been able to establish where the steam is coming from.

The news comes a day after Tepco admitted for the first time that radioactive contaminated water is still leaking from the plant in to the sea.

Rupert Wingfield Hayes reports from Tokyo.