A US Air Force investigation into exam cheating by America's nuclear missile officers has widened.
A US official has said, speaking on condition of anonymity, that roughly double the original 34 officers are now under review.
The Air Force disclosed earlier this month that 34 officers were under investigation, either for cheating on a key proficiency exam last year or for knowing about the cheating and failing to report it.
Some nuclear officers have also been implicated in an investigation into illegal drug possession.
Defence Secretary Chuck Hagel last week ordered a high-level review of the US nuclear forces, saying he was "deeply concerned" about morale and discipline among nuclear officers.
Still, he insisted US nuclear arms were safe.
An Air Force spokesman confirmed that the number of officers under investigation in the cheating scandal had increased from the original 34, but declined to offer a precise number "to protect the integrity of the investigation".
A US official, speaking to Reuters on condition of anonymity, said the number of officers under investigation had roughly doubled.
The scandals are raising questions about how to keep up morale of the nuclear force in the post-Cold War era, when officers face the pressure of guarding the world's most destructive weapons without the recognition of other high-profile missions.
The investigations also come just months after the head of the ICBM force, Air Force Major General Michael Carey, was fired for getting drunk and carousing with women last year while leading a government delegation to Moscow for talks on nuclear security.