Japan pledged nearly $500 million (RM1.64 billion) to contain leaks and decontaminate radioactive water from the tsunami-crippled Fukushima nuclear plant, stepping up government efforts to cope with the legacy of the worst atomic disaster in a quarter of a century.

The announcement comes just days before the International Olympic Committee decides whether Tokyo - 230 km (140 miles) from the wrecked plant - will host the 2020 Olympic Games and the government is keen to show the crisis is under control. Madrid and Istanbul are the rival candidates.