(Adds Pentagon comments in paragraphs 10-11)
By Phil Stewart
WASHINGTON, Jan 29 (Reuters) - The U.S. Air Force is likely suffering from a "systemic problem" among the officers who oversee America's nuclear missile launch systems, the new head of the military branch said on Wednesday as an exam-cheating scandal widened.
"The need for perfection has created way too much stress and way too much fear about the future," Air Force Secretary Deborah Lee James told an Air Force Association forum near the Pentagon.
The scandal over a monthly proficiency exam was the largest single case of cheating in recent memory in America's nuclear missile forces, which already face growing questions over discipline and morale in the post-Cold War era.
An initial investigation implicated 34 officers, but a U.S. official told Reuters on Tuesday that the number has roughly doubled.
"We likely do have ... a systemic problem in this," James said.
She also raised concerns about the force's testing culture, key to promotion within the force, that many nuclear missile officers felt was largely punitive.
James, who visited the officers last week, said the Air Force needed to "reinvigorate our campaign on core values."
"Airmen need to understand that being a good wingman does not mean protect others who lack integrity," she said.
"I heard over and over again, airmen don't want to be perceived as reporting on their buddies. That's not good when it comes to matters of integrity."
At the Pentagon, Defense Secretary Chuck Hagel heard from James and others about concerns surrounding nuclear force personnel, spokesman Rear Admiral John Kirby said.
"The general consensus in the room was that we all need to accept the reality that there probably are systemic issues in the personnel growth and development inside the nuclear mission," Kirby told reporters.
James said an ongoing review would also examine whether the Air Force needs to provide better incentives -- perhaps pay or scholarships -- to make the career field more attractive.
She added that despite the review, the nuclear mission and the weapons themselves were "safe, secure and reliable."
The scandal emerged earlier this month after the Air Force said missile launch officers at Malmstrom Air Force Base in Montana shared answers on a monthly proficiency exam through text messages last year.
The Air Force also is investigating claims of illegal drug possession by other nuclear officers. That comes months after the head of the U.S. intercontinental ballistic missile force, Air Force Major General Michael Carey, was fired in October for getting drunk and carousing with women while leading a government delegation to Moscow for talks on nuclear security. (Reporting by Phil Stewart; Editing by Amanda Kwan)