The Japanese government has made it illegal to enter a 20 km evacuation zone around the Fukushima Daiichi nuclear facility.
People were urged to leave the area shortly after the 11 March earthquake and tsunami crippled the plant, but the order was not enforced by law. According to the BBC, brief re-entry will be allowed to the area's 80,000 former residents to collect belongings.
It is not clear how many people are still living in the evacuation zone, but reports said police had counted at least 60 families. After the disaster the government also declared a wider 10 km zone around the 20 km evacuation area where people should either stay indoors or leave.
It later recommended that people also evacuate parts of that area as well. "The plant has not been stable," said the chief government spokesman, Yukio Edano.
"We have been asking residents not to enter the area as there is a huge risk to their safety," he said. "Unfortunately, there are still some people in the areas. Today... we have decided to designate the area an emergency area based on disaster law."
Most of the evacuees are living in sports hall and gymnasiums waiting to return home.
It could be a long wait, said the BBC, as the plant's operator, Tokyo Electric Power (Tepco), has said it aims to bring the reactors to a cold shutdown within nine months. The evacuation zone will be reassessed then, adds our correspondent.
Residents would be allowed supervised visits of two hours to collect belongings, which would be screened for radiation contamination.
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