In the 1950s, the United States secretly maintained nuclear weapons on two Japanese islands occupied by American military forces as a result of agreements ending World War II, according to an article in Monday's Bulletin of the Atomic Scientists.

More than 500 miles away from the Japanese mainland, the islands of Chichi Jima and Iwo Jima were used to store American nuclear bombs and missiles for U.S. submarines and bombers in the event of a nuclear war, the article says.

Although the storage of these weapons on American-occupied islands meant the United States technically abided by Japan's non-nuclear principles, "the non-nuclear status of the country was fundamentally undermined," according to William Arkin, one of the authors.

The new disclosures came as a result of further research by the authors, who in an earlier article mistakenly identified Iceland as the "I" country listed among 15 foreign sites in a declassified Pentagon report that identified where U.S. nuclear weapons were stored during the Cold War.

"That 'I' country turned out to be Iwo Jima," said Robert S. Norris, another of the authors. Chichi Jima was the "C" country that they had earlier not been able to identify, he added.

When U.S. military occupation ended in 1951, the two islands stayed under American control with nuclear weapons remaining until the mid-1960s. The weapons were withdrawn from Iwo Jima in 1959 and Chichi Jima in 1965, according to the article. However, when the islands were returned to Japan, a secret 1968 agreement was in effect that granted the United States the right to store weapons there in a military emergency, according to the authors.

Norris said yesterday he expects the article to be "big news in Japan and raise questions about who in the Japanese government knew and agreed to these programs."

Because the Japanese people have been the only ones to experience the impact of nuclear weapons, the governments there have kept up the facade that no weapons would ever be produced, possessed or introduced on their territory.

Over the years, however, there have been public protests about U.S. Navy ships that carry nuclear weapons making port calls and regular stories about American weapons being stored on Okinawa, another U.S.-occupied, Japanese-owned island.

During this period, and continuing today, the U.S. government policy has been neither to confirm nor deny the presence of nuclear weapons at any site. Throughout the Cold War, Japanese leaders, starting with Prime Minister Nobusuke Kishi, maintained that their country would neither develop nuclear weapons nor permit them on its territory.