The U.S. Air Force has released a report revealing hundreds of instances of pornography on its bases. The investigation was spurred by a female sergeant who risked her career by stepping forward. NBC's Michael Isikoff reports.

A worldwide inspection of U.S. Air Force facilities uncovered more than 631 pornographic movies, videos, DVDs, posters, magazines and other material that were either stored on computer servers or displayed in common areas at bases, according to a report released Friday. The hunt also found 31,585 other instances of "unprofessional" and "offensive" material -- including some that was racially insensitive, it said.

The search and report come on the heels of allegations that sexual misconduct is rampant within the Air Force and mounting complaints from Congress and women's groups that the service has tolerated a "culture" of disrespect for women. Other branches of the U.S. military have been the subject of similar complaints.

Maj. Joel Harper, an Air Force spokesman, confirmed that criminal investigations have been launched into some of those responsible for the material and said that some personnel may be subject to possible court martials. All the pornography and offensive material has been either removed or destroyed, Harper said.

The purpose of the inspection was "to send a message that this type of stuff is not acceptable in this day and age," Harper said. "Some of this was clearly inappropriate."

Mattel The 'offensive' material seized at Air Force bases around the world ran the gamut from hard-core pornography to a 'Ken' doll clad only in swimming trunks.

An especially high number of improper materials were found at the Air Education and Training Command in Texas, which includes Lackland Air Force Base, the report said. More than 30 instructors there are already under investigation for sexual misconduct—including allegedly sexually assaulting trainees -- and the issue will be a subject of a hearing before the House Armed Services Committee next week. Among the material found at the command on common computer drives, according to the report, were 144 pornographic posters and graphics -- including some "glorifying suicide" and "racial" in nature -- and 13 videos at showing "sexual images" as well as "killings and torture." Another video removed from the command was entitled "Achmed the Dead Terrorist."

Material found and removed at other bases included Maxim magazines "with scantily clad women in provocative poses" and photos of a "clothed lady performing oral sex" and a "female in tank top with beer bottle between breasts," it said. Other less explicit material, deemed less serious but still inappropriate, included a shirtless photo of New England Patriots quarterback Tom Brady and a “Ken' Doll dressed only in swim trunks."

The worldwide inspection of all Air Force bases was ordered last month by Gen. Mark Welsh, the service’s Chief of Staff, who directed commanders to “document and remove as contraband” any material they deemed “unprofessional or inappropriate” – defined as “detrimental to a professional working environment” as well as “lewd, obscene or pornographic images or publications.” Harper said it was up to individual commanders to determine what constituted “inappropriate” materials.

Welsh acted after Jennifer Smith, a technical sergeant at Shaw Air Force Base, filed an administrative complaint alleging "systemic and intentional sexual discrimination" against women in the Air Force. Smith, a 17 year veteran of the Air Force, told NBC News that she found highly offensive and "disgusting" pornography stored on computer servers and in songbooks at the base -- as well as some that she said were stored in classified vaults.

"I have served just as long and just as hard as any male has and for them to put that type of pornography out there was degrading," she said.

As the numbers of women serving in the military has increased over the years, it has led to mounting complaints of rapes, sexual assaults and other misconduct. The Pentagon estimated that there had been as many as 19,000 sexual assaults against members of the military in 2011, and Defense Secretary Leon Panetta vowed vigorous action to attack the problem.

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