Tokyo/Fukushima: With no sign of its atomic crisis ending soon, Japan on Thursday said it would ban entering a 20-km evacuation zone around the radiation-leaking Fukushima nuclear plant, as Premier Naoto Kan vowed to make all-out efforts to help those affected rebuild their lives.

The legally-controlled off-limits zone around the plant, which is being enforced for the first time, covers about 27,000 households in nine municipalities, from where the government had already asked residents to evacuate.

Chief Cabinet Secretary Yukio Edano said the no-entry zone is aimed at protecting the health and safety of residents as some of them have been returning home without sufficient safety measures.

Anyone entering the banned area could be subject to fines. The government also said it would allow one member of each household to temporarily return to their homes in the off-limits zone. But it has decided not to allow visits for residents living within three kilometres of the nuclear plant.

Prime Minister Kan then visited the national nuclear disaster task force in Fukushima and said the central government has to make all-out efforts so that local residents can rebuild their lives.

He asked officials of the task force to step up their efforts in helping revitalise Fukushima and the rest of Japan in what he said could be a long battle.

Japan tsunami claimed mainly elderly

New data from Japan's National Police Agency shows that two-thirds of the victims identified so far in the last month's tsunami were elderly, and most of them drowned.

The agency said in a release that 65 percent dead (11,108) were older than 60.

Another 1,899 identified victims were of unknown age. Adding those who are still missing, the disaster killed an estimated 27,500 people.

The agency also reported that nearly 93 percent of the victims had drowned. Others died from fires, being crushed or other causes.

The earthquake and tsunami hit the rural, northeastern coast where there were higher concentrations of elderly residents.