FUTABA, Japan (AP) ― Japan sealed off a wide area around a radiation-spewing nuclear power plant Friday to prevent tens of thousands of residents from sneaking back to the homes they quickly evacuated, some with little more than a credit card and the clothes on their backs.

Fearing they might not see their homes again for months, evacuees raced into the deserted towns Thursday before the ban took effect to grab whatever belongings they could cram into their cars.

“This is our last chance, but we aren’t going to stay long. We are just getting what we need and getting out,” said Kiyoshi Kitajima, an X-ray technician, who dashed to his hospital in Futaba, a town next door to the plant, to collect equipment before the order took effect at midnight.

Nearly 80,000 people were hurriedly evacuated from a 20-kilometer zone around the Fukushima Daiichi plant on March 12, after an earthquake and a tsunami destroyed its power and cooling systems. The order had no teeth, however, and people began increasingly returning to check on the remains of their lives. Some had stayed all along.

With ongoing concerns about radiation exposure ― as well as theft in the mainly deserted zone ― government officials imposed the formal closure barring anyone from entering the area.

Under a special nuclear emergency law, people who enter the zone will now be subject to fines of up to 100,000 yen ($1,200) or possible detention for up to 30 days. Until now, defiance of the evacuation order was not punishable and the police manning the roadblocks had no authority to stop people from entering.

“We beg the understanding of residents. We really want residents not to enter the areas,” Chief Cabinet Secretary Yukio Edano told reporters.

The order angered some residents who had fled nearly empty-handed when told to evacuate.

“I initially thought we would be able to return within a few days. So I brought nothing except a bank card,” said Kazuko Suzuki of Futaba.

“I really want to go back. I want to check if our house is still there,” said the 49-year-old woman, who fled with her teenage son and daughter. “My patience has run out. I just want to go home.”