Obama vows 'no tolerance' for military sexual assault

US President Barack Obama sharply warned Tuesday there would be "no tolerance" for the "outrage" of sexual violence in the military, and said those guilty of such crimes had betrayed their uniform.

Obama said he stood squarely behind victims of sexual assault in the military and called on the Pentagon to up its game, after the head of the US Air Force's rape prevention program was charged with sexual battery.

"Sexual assault is an outrage. It is a crime. That's true for society at large, and if it's happening inside our military, then whoever carries it out is betraying the uniform that they're wearing," Obama said.

"We're not going to tolerate this stuff. There will be accountability."

Obama, the commander-in-chief of the US armed forces, said he spoke to Defense Secretary Chuck Hagel Tuesday about the latest reports of sexual assaults and said the military must "exponentially" up its game on the issue.

"If we find out somebody's engaging in this stuff, they have got to be held accountable, prosecuted, stripped of their positions, court-martialed, fired, dishonorably discharged -- period.

"It's not acceptable," Obama said at a White House news conference.

Hagel separately told reporters that a spate of sexual violence risked undermining trust in the military, and pledged to hold commanders responsible.

"This department may be nearing a stage where the frequency of this crime, and the perception that there is tolerance of it, could very well undermine our ability to effectively carry out the mission and to recruit and retain the good people we need," he said.

"That is unacceptable to me and the leaders of this institution."

The arrest of Lieutenant Colonel Jeff Krusinski brought the issue of sexual assault in the US military to the fore again after several recent scandals.

Krusinski allegedly "approached a female victim in a parking lot and grabbed her breasts and buttocks," according to a police report from Arlington, Virginia, the location of the Pentagon, just outside the US capital.

"The victim fought the suspect off as he attempted to touch her again and alerted police," the police report said.

Krusinski, 41, was charged with sexual battery and held on a $5,000 bond.

Air Force officials confirmed to AFP that Krusinski was head of the service's rape prevention program and said he has been removed from his post.

The Pentagon meanwhile released a report to Congress outlining a six percent rise in reported sexual assaults in the military in 2012 and a spike in anonymous claims of "unwanted sexual contact."

"Sexual assault is a persistent problem that remains vastly under-reported," the report warned.

Incidences of sexual assaults involving troops as victims or suspects rose to 3,374 in 2012, from 3,192 the year before, the report said.

The number of people who made an anonymous claim that they had "unwanted sexual contact" but never reported the attack rose dramatically, from 19,000 in 2011 to 26,000 men and women in 2012, it said.

In 66 percent of cases, the accused were prosecuted in court martials or received administrative punishment.

There is growing outrage over the issue in Congress, where lawmakers are pushing legislation to address the problem, including bills that would prevent commanders reviewing convictions or sentences by military courts.

Hagel has also proposed removing authority from commanders to overturn a verdict after a court martial.

The Air Force has recently come under severe criticism after a general recently tossed out a conviction from a court martial against a fighter pilot, Lieutenant Colonel James Wilkerson.

And the Air Force has been reeling from a scandal at its main training center in Lackland, Texas, where more than a dozen training instructors have been accused of misconduct with recruits, including sexual assault.

Lawmakers have slammed the Air Force and the broader military over sexual assault cases, saying the Pentagon has failed to come to grips with the problem.

Obama said he was fed up of talking about fixes and wanted answers.

"We're going to communicate this again to folks up and down the chain in areas of authority. And I expect consequences," he said.

"I don't want just more speeches or awareness programs or training, but, ultimately, folks look the other way."