Male survivors of rape while serving in the military say they are often deemed "liars and troublemakers" when they report abuse.

The Pentagon estimated about 13,000 of the 1.2 million men serving in the military suffered sexual assault last year, NBC News reported. About 12,100 of the 203,000 women in uniform were sexually assaulted on active duty last year.

The Defense Department has said men "report at much lower rates than female survivors."

Brian Lewis, a rape survivor who served in the Navy, said that is because male survivors are "still viewed as having wanted it."

"As a culture, we've somewhat moved past the idea that a female wanted this trauma to occur, but we haven't moved past that for male survivors," Lewis said. "In a lot of areas of the military, men are still viewed as having wanted it or of being homosexual. That's not correct at all. It's a crime of power and control."

"But also, you're instantly viewed as a liar and a troublemaker [when a man reports a sex crime], and there's the notion that you have abandoned your shipmates, that you took a crap all over your shipmates, that you misconstrued their horseplay," Lewis said.

"The biggest reasons men don't come forward [with sex assault reports] are the fear of retaliation [from fellow troops], the fear of being viewed in a weaker light and the fact there are very few, if any, services for male survivors," Lewis told NBC News.

President Obama said though the military is ashamed of the situation there's "no silver bullet" for solving the sexual assault problem.

Sex crimes in the military are "dangerous to our national security" and "not a sideshow," Obama said at the White House after meeting with Defense Secretary Chuck Hagel, Joint Chiefs of Staff Chairman Martin Dempsey and the leaders of the Army, Navy, Air Force and Marine Corps, as well as senior enlisted advisers to discuss the rise in military sexual assaults.

Hagel and the senior uniformed officers told Obama at the meeting they were "angry" about the sexual-assault rise, Obama told reporters in the Cabinet Room. "And I heard directly from all of them that they're ashamed by some of what's happened," Obama said.

Newsweek reported two years ago women in the military were more likely to be assaulted by a fellow soldier than killed in combat.

Obama said Thursday he and the others at the meeting suggested a number of ideas to get at the longstanding problem, whose string of misconduct cases included the Army saying Tuesday a sergeant in charge of preventing sexual assaults at Fort Hood, Texas, was being criminally investigated for alleged "abusive sexual contact."

Ten days earlier, the Air Force's top sexual-assault-prevention officer was arrested on charges he drunkenly groped and battered a woman in a parking lot near the Pentagon.

With those as a backdrop, the military leaders suggested to Obama creating incentives so top military officers "understand this is as core to our mission as anything else," Obama said. They also suggested "empowering victims" so they can come forward and report the crimes with "no fear of retaliation" and know they'll get justice, Obama said.

Hagel will also look for "best practices" by seeing how other countries' militaries handle sex crimes, Obama said.

"There is no silver bullet to solving this problem," Obama cautioned. "This is going to require a sustained effort over a long period of time."

Before the meeting, several military commanders acknowledged their failure to get at the problem.