ARLINGTON, Va. — Defense workers accidentally shipped four highly classified triggers for nuclear intercontinental missiles to Taiwan in 2006, where they sat undetected in a warehouse until last Thursday, defense officials said.

The parts, which are the firing mechanisms that sit in the nose cone of a Minuteman missile, were sent instead of unclassified helicopter batteries the military was selling to Taiwan, Air Force Secretary Michael Wynne told reporters on Tuesday.

After Taiwan notified U.S. officials Thursday of the mistake, U.S. Pacific Command officials immediately sent military liaisons to the warehouse to secure the parts, Wynne said.

U.S. officials are investigating how the fuses — which contain no nuclear material, but are essential to the missile’s operation — were shipped in the first place, and how they were overlooked for so long, Wynne said.

“We are very concerned about it,” he said.

The issue is particularly sensitive, because China objects to U.S. defense assistance to Taiwan.

Ryan Henry, the No. 2 policy official in the office of Defense Secretary Robert Gates, called the mistake “disconcerting” and intolerable and said the Chinese government has been notified of the error.

Both Henry and Wynne also said that an examination of the site in Taiwan where the components had been stored after delivery indicated that they had not been tampered with.

The Chinese Embassy and Taiwan officials did not immediately respond to requests for comment from The Associated Press.

Officials believe the mix-up began in 2005, when the fuses were declared as excess inventory at F.E. Warren Air Force Base in Cheyenne, Wyo.

The fuses — which look nothing like helicopter batteries, Wynne said — were sealed inside circular containers about 22 inches in diameter, one fuse per container, and shipped to a Defense Logistics Agency warehouse in Utah where there is classified and nonclassified storage.

“These went to unclassified storage. They should have gone to classified storage,” he said.

DLA workers are supposed to conduct a quarterly inventory check to make sure all classified material is accounted for, Wynne said, but the absence of the four classified missile fuses was overlooked at least six times. Part of the investigation under way will be to determine how that happened.

“This clearly is an escape from the process,” Wynne said.

Air Force and Joint Staff officials learned of the fuses’ existence Thursday afternoon, Henry said. Gates was notified Friday morning, and he spoke to President Bush about the actions to recover the fuses and investigate the incident.

The United States follows a “one China” policy that recognizes that self-ruled Taiwan is part of the communist country. But the U.S. remains the island’s most important foreign backer, providing it with the means to defend itself against a possible Chinese attack.

China and Taiwan split amid civil war in 1949. Beijing continues to claim the island as part of its territory and has threatened to attack if Taiwan formalizes its de facto independence.

The Associated Press contributed to this story.

Sign Up for Daily Headlines

Sign up to receive a daily email of today's top military news stories from Stars and Stripes and top news outlets from around the world.

Sign Up Now