WASHINGTON — Armed security forces at a nuclear missile base failed a drill last summer that simulated the hostile takeover of a missile launch silo because they were unable to speedily regain control of the captured nuclear weapon, according to an internal Air Force review obtained by The Associated Press.

The previously unreported failure, which the Air Force called a “critical deficiency,” was the reason the 341st Missile Wing at Malmstrom Air Force Base in Montana flunked its broader safety and security inspection.

The security team was required to respond to the simulated capture of a Minuteman 3 nuclear missile silo, termed an “Empty Quiver” scenario in which a nuclear weapon is lost, stolen or seized. Each of the Air Force’s 450 Minuteman 3 silos contains one missile armed with a nuclear warhead and ready for launch on orders from the president.

The review obtained by the AP through a Freedom of Information Act request sought to examine why the security force showed an “inability to effectively respond to a recapture scenario.” It cited their failure to take “all lawful actions necessary to immediately regain control of nuclear weapons” but did not specify those actions.

The prize for terrorists or others who might seek to seize control of a missile would be the nuclear warhead attached to it. In 2009, the Air Force cited a “post-9/11 shift in thinking” about such situations, saying that while this nightmare scenario once was considered an impossibility, the U.S. “no longer has the luxury of assuming what is and what is not possible.”