Sexual assaults in the U.S. military are a growing epidemic across the services, and thousands of victims are still unwilling to come forward despite a slew of new oversight and assistance programs, according to Pentagon documents.

Troubling new numbers estimate that up to 26,000 military members may have been sexually assaulted last year, according to survey results released against a backdrops of scandals that include an ongoing investigation into more than 30 Air Force instructors for assaults on trainees at a Texas base.

The report comes just days after the Air Force’s head of sexual assault prevention was arrested on charges of groping a woman in a suburban Virginia parking lot. And it follows a heated debate over whether commanders should be stripped of the authority to overturn military jury verdicts, such as one officer did in a recent sexual assault conviction.

President Barack Obama delivered a sharp rebuke Tuesday, saying he has no tolerance for the problem, adding he talked to Defense Secretary Chuck Hagel about it. He said any military member found guilty of sexual assault should be held accountable, prosecuted and fired.

“I don’t want just more speeches or awareness programs or training, or ultimately folks look the other way,” he said. “We’re going to have to not just step up our game, we have to exponentially step up our game to go after this hard.”

New Pentagon documents show the number of sexual assaults actually reported by members of the military rose 6 percent in 2012, to 3,374. But an anonymous survey of personnel showed the number of service members actually assaulted could be as many as 26,000, but they never reported the incidents, officials said Tuesday. In 2011, the estimated number of assaults was 19,000.

The statistics highlight the dismal results military leaders have achieved in their drive to change the culture within the ranks, even as the services redoubled efforts to launch new programs to assist the victims, encourage reporting and increase commanders’ vigilance.

Hagel ordered military leaders to develop a method to assess commanders and hold them accountable on their ability to create a climate “of dignity and respect.” He has given commanders until July 1 to visually inspect workspaces to make sure they are free of degrading materials, and military leaders have until Nov. 1 to recommend ways to assess officers and hold them accountable for their command climates.

“Sexual assault is a crime that is incompatible with military service and has no place in this department,” Hagel said in a new response plan. “It is an affront to the American values we defend, and it is a stain on our honor. (The Department of Defense) needs to be a national leader in combating sexual assault and we will establish an environment of dignity and respect, where sexual assault is not tolerated, condoned, or ignored.”

In Congress, lawmakers demanded the Pentagon take more aggressive steps to address the growing problem, and they announced renewed efforts to pass legislation to battle the problem.

Members of Congress are putting together legislation to essentially strip military officers of the authority to overturn convictions for serious offenses such as sexual assault. The measure stems from congressional outrage over an Air Force officer’s decision to reverse a jury verdict in a sexual assault case.

While the latest cases involve Air Force members, the problem extends across all the military services.