The U.S. Air Force pulled the nuclear launch clearances of 17 crew members last month without saying a word publicly, The Associated Press has learned.

The unprecedented move was sparked after crew members were given near failing grades on a simulated ICBM launch in March. One month later, 17 members of the 91st Missile Wing, stationed in North Dakota's Minot Air Force Base, were suspended. Disciplinary actions are also pending against an 18th crew member for purposefully violating rules in such a way that could have compromised nuclear launch codes, the AP noted.

Asked about this during a Senate hearing on Wednesday, Air Force Secretary Michael Donley acknowledged that the inspection problems were behind the suspensions. "We substantially strengthened the inspection process, and what you're seeing and hearing reported in the article you mentioned reflects the inspection process we have put in place," he told Sen. Dick Durbin (D-IL).

An email sent to the unit in April by its commander, Lieutenant Colonel Jay Folds, was obtained by AP. It explains that a lackadaisical attitude had developed in the unit, which works in an area of the military that has largely been sidelined and relatively inactive since the collapse of the Soviet Union.

Folds told the 17 crew members that they would "be a benchwarmer for at least 60 days," and expressed his disappointment in their performance by saying they had "fallen" and must be retrained. "We are breaking you down, and we will build from the ground up," he added. "It takes real leaders to get through a crisis and we are, in fact, in a crisis right now."

Donley's take was substantially softer. "Generally, the inspection was satisfactory, but it was rated marginal in one area in particular," he said during Wednesday's hearing. "And this is an area where the group commander is following up, to make sure that the officers involved are focused as they need to be on all the details of their mission and that they have the appropriate focus exactly where it needs to be. So, we support commanders following up on inspections with those actions they think are necessary to maintain the highest professional standards."

The Air Force Secretary went on to explain that "these are lieutenants, by and large, some of them can be new to the Air Force," and "within their first few years, so the training process that we have for the nuclear mission has the highest standards, but needs to be reinforced continually, every day, every week, every month, throughout the year as there are new people coming into the system."

"It is cold comfort to hear that these are lieutenants who may have been new to this job," Durbin replied.

The unit has 150 crew members whose duty it is to hold a constant guard over the nation's nuclear arsenal and maintain its launch-capable ICBMs, AP noted. Many young lieutenants, if they entered the service directly after college, are likely be in their mid to late 20s.

Minot Air Force Base is the same base where six nuclear-tipped warheads were mistakenly loaded onto bombers in 2007 and flown to Louisiana, in a stunning mistake that violated a key treaty and caused the Air Force to investigate lapses among officers overseeing America's arsenal.

Donley was brought on shortly thereafter, and he told Durbin Wednesday that the mistaken flight was the "proximate cause" for his hiring.


Megan Carpentier contributed to this report.

Photo: U.S. Air Force / Senior Airman Jesse Lopez. Description: Members of the 91st Missile Maintenance Squadron here, were instrumental in ensuring the last Propulsion System Rocket Engine upgrade for the nation's Minuteman III Intercontinental Ballistic Missiles, was accomplished successfully. The upgrades were part of Air Force Global Strike Command's Life Extension Program designed to lengthen the life of the missile fleet.