Former Prime Minister Junichiro Koizumi has thrown his support behind a group of former U.S. sailors suing the operator of the Fukushima No. 1 nuclear plant. The sailors claim health problems they now suffer were caused by exposure to radiation after a triple meltdown at the plant following an earthquake and tsunami in March 2011.

Speaking at a news conference Tuesday in Carlsbad, California, with some of the plaintiffs, Koizumi said, "Those who gave their all to assist Japan are now suffering from serious illness. I can't overlook them."

The lawsuit was lodged in 2012 against plant operator Tokyo Electric Power Co., which was last month renamed Tokyo Electric Power Company Holdings Inc.