WASHINGTON (AP) — Air Force officials say a unit responsible for operating nuclear missiles has failed a safety and security inspection.

As described to The Associated Press on Tuesday by Air Force Lt. Gen. James M. Kowalski, the 341st Missile Wing at Malmstrom Air Force Base, Mont., failed a nuclear safety and security inspection this week.

This is the second major setback this year for the Air Force's nuclear weapons force, which is responsible for 450 land-based nuclear missiles on 24/7 alert for potential launch at targets around the globe.

Last spring a missile unit in North Dakota received weak grades on an inspection but did not fail it outright; that performance was so poor, however, that 17 officers temporarily lost their authority to operate missiles.

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