Photo/IllutrationFormer Prime Minister Junichiro Koizumi breaks down in tears at a May 17 news conference in Carlsbad, California, after talking about what U.S. veterans who took part in Operation Tomodachi have endured. (Ari Hirayama)

CARLSBAD, California--Former Prime Minister Junichiro Koizumi broke down in tears as he made an emotional plea of support for U.S. Navy sailors beset by health problems they claim resulted from radioactive fallout after the 2011 nuclear disaster.

More than 400 veterans who were part of a mission called Operation Tomodachi to provide humanitarian relief after the Great East Japan Earthquake and tsunami filed a mass lawsuit in California against Tokyo Electric Power Co., operator of the crippled Fukushima No. 1 nuclear plant. They are seeking compensation and an explanation for their health problems.

Koizumi, 74, responded to a request from a group supporting the plaintiffs and flew to the United States to meet with 10 veterans.

At a news conference here on May 17, Koizumi said: "U.S. military personnel who did their utmost in providing relief are now suffering from serious illnesses. We cannot ignore the situation."

Apparently overcome with emotion, Koizumi started crying, but went on and said, "Proponents and opponents of nuclear energy must think together about what can be done."

Koizumi, in power between 2001 and 2006, became a vocal opponent of nuclear energy after the triple meltdown at the Fukushima plant caused by the magnitude-9.0 earthquake and tsunami.

During the news conference, Koizumi also touched upon the significance of the scheduled visit to Hiroshima by U.S. President Barack Obama next week.

"It will be important to see how that is tied into a reduction and eventual elimination of nuclear weapons," Koizumi said. "We should all work toward zero nuclear plants and develop other energy sources."

Most of the plaintiffs in the lawsuit were crew members of the nuclear-powered aircraft carrier USS Ronald Reagan, which anchored off the Tohoku coast to provide relief along the battered coastline.

Theodore Holcomb, an aviation mechanic on the flattop, was tasked with washing down U.S. helicopters that had operated in areas with high radiation. He was later diagnosed with synovial sarcoma, a rare form of cancer. He died in 2014 at age 35.

The Department of Veterans Affairs later cut off a study into the causal relationship between his exposure to radiation and his illness.

His best friend in the Navy, Manuel Leslie, 41, now is one of the plaintiffs in the lawsuit on behalf of Holcomb.

Leslie said he just wants the truth to come out for his friend.

Another crew member, Ron Wright, 26, worked on the deck. After finishing his shift one day, he was forced to remove his clothes after a high radiation reading. Subsequently, he developed a swelling of the testicles and underwent surgery four times after he returned to the United States. However, the pain was so intense that he had to rely on painkillers and sleeping pills.

A military doctor told him there was no relationship between his illness and exposure to radiation.

Wright said he was never given protective clothing or iodine during the mission. He also said he had no knowledge of radiation at the time.

According to the ship's logs and the testimony of former crew members, sailors aboard the Ronald Reagan may well have been exposed to radiation as the carrier passed under a radiation plume that was generated by the Fukushima accident. In addition, the carrier used desalinated seawater for drinking and showers by crew members.

However, in a 2014 report released by the U.S. Defense Department, no link was established between radiation exposure and health problems. The reason cited was that only a low level of radiation exposure occurred.

Many of the plaintiffs have not been compensated for their medical expenses.

Paul Garner, a lawyer for the plaintiffs, said, "I hope the Japanese people will realize there are American 'tomodachi' who have been forgotten."

A spokesperson for Tokyo Electric Power Co. Holdings Inc. said, "We are dealing with the matter through the normal channels."

(This article was written by Masato Tainaka and Ari Hirayama.)