WASHINGTON – Members of a House panel angry over the growing epidemic of sexual assaults in the military took a key step toward tackling the problem by passing legislation Wednesday that would strip commanding officers of their longstanding authority to unilaterally change or dismiss court-martial convictions in rape and assault cases. Lawmakers believe the revision will lead to a cultural shift and encourage victims to step forward.

The legislation, which will be folded into a broader defense policy bill also would impose harsher penalties on service members found guilty of sexual offenses by requiring that they be dismissed or discharged.

The moves by the House Armed Services military personnel subcommittee reflect outrage on Capitol Hill over the poor results military leaders have achieved in their efforts to combat sexual assault in the ranks. A Pentagon report released earlier this month estimated that up to 26,000 military members may have been sexually assaulted last year and that thousands of victims are still unwilling to come forward despite new oversight and assistance programs. The report showed the number of sexual assaults officially reported by members of the military rose 6 percent to 3,374 in 2012. But a survey of personnel who were not required to reveal their identities showed the number of service members actually assaulted could be as high as 26,000. That figure is an increase over the 19,000 estimated assaults in 2011.

Congress has repeatedly challenged the military to take more aggressive steps to curb sexual assault. The subcommittee’s vote came after a string of incidents that raised fresh doubts about the military’s commitment to tackling the problem.

In the latest, the Army said Wednesday that a soldier has been charged with secretly photographing and videotaping women at the U.S. Military Academy at West Point, including in a bathroom. Sgt. 1st Class Michael McClendon is facing charges that include taking and possessing inappropriate photos and videos of at least a dozen women.

Rep. Joe Wilson, R-S.C., the military personnel subcommittee chairman, said the proposed changes are significant and will give assault victims the confidence to report crimes.

Rep. Michael Turner, R-Ohio, who along with Rep. Niki Tsongas, D-Mass., wrote several of the provisions included in the subcommittee’s bill, criticized the Defense Department’s approach to the problem.

“I think the leadership of the military is confused,” Turner said. “They believe as long as they have programs where they say sexual assault is wrong that they’ve done enough. No. They have to support the victim, and they have to support vigorous prosecution.”