(CNN) -- Reports of sexual assault in the U.S. military are up 50%, according to the latest annual figures reported on Thursday by the Pentagon.
The Defense Department said the sharp increase follows steps over the past year to encourage alleged victims to come forward to report such abuse and reflects more confidence in how the military responds. There is no indication the spike was due to an overall increase in actual incidents, officials said.
There were 5,061 sex assault reports in the 2013 fiscal year, which ended last September 30. That represents a 50% increase from the same period the year before.
Although the Pentagon has taken steps to address the matter following the release of troubling statistics last spring, Defense Secretary Chuck Hagel said officials still believe the issue is under-reported and there is more work to do.
One area of focus is to get more male victims to file claims.
"The best way to combat this crime is to prevent it," Hagel said, adding the armed forces must "live our core values and we must each be responsible for our actions."
Hagel said victims of sexual assault are "not only human beings, they are fellow soldiers, sailors and Marines. We cannot let them down."
The issue received heightened attention from the Obama administration and Congress after last year's report also showed a startling jump in reported sex assault claims.
Rep. Niki Tsongas, co-chair of the Military Sexual Assault Prevention Caucus and the top Democrat on the House Armed Services Subcommittee for Oversight and Investigations, said the figures continue to indicate a serious problem.
"The rise in reporting is encouraging, possibly signaling that legislative and military changes from recent years are having a positive impact," she said in a statement.
But Tsongas added better reporting and other steps to address the issue "does not obviate the simple fact that these heinous crimes continue to occur at an alarming rate, to both men and women."
Sex assault in the military has become a major concern for the Pentagon over the past year.
An anonymous survey from 2012 found that nearly 26,000 service members said they were the victim of an incident of sexual assault or unwanted sexual contact. But only a fraction actually filed a report.
President Barack Obama demanded the military brass "leave no stone overturned" in efforts to prevent abuse.
Directives from this year's report include calls to advance and sustain an appropriate culture within the military to report incidents as well as increased efforts to evaluate commander training in dealing with the issue.
There have been several instances in which senior officers, including generals, have been accused or charged with a variety of actions that constitute sexual assault. Some actually oversaw programs that sought to combat sexual assault.
The report also calls for a review of alcohol policies and highlights an effort to improve levels of reporting for male victims, long thought to be an under-reported demographic.
According to military law, sexual assault is defined as intentional sexual contact characterized by use of force, threats, intimidation, or abuse of authority or when the victim does not or cannot consent.
It also includes categories of sexual offenses that include rape, sexual assault, aggravated sexual contact, abusive sexual contact, forcible sodomy, or attempts to commit these acts.
The issue also generated outrage in Congress, which approved reform measures last year that included a provision preventing commanders from overturning convictions.
The Senate sought to take things further, approving legislation this year imposing modest reforms to strengthen prosecution. But proponents of tougher action were disappointed the chamber rejected a proposal that would have altered the way crimes like sex assault and rape are handled.