Defense Secretary Chuck Hagel has made the rare gesture of phoning Air Force nuclear officers in their underground launch bunkers in Montana to update them on efforts to correct problems in their service.

Hagel placed the calls from aboard the military command aircraft that ferried him home Saturday from an international security conference in Germany.

The Pentagon chief spoke to a total of six Minuteman 3 missile launch control officers — two in each of three launch centers operated by the 341st Missile Wing at Malmstrom Air Force Base in Montana.

Malmstrom is the focus of a widening investigation into alleged cheating by launch officers on proficiency tests. Half of the 183 launch officers at the base have been implicated in the cheating investigation and suspended.

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