WASHINGTON (AFP) - The US Army's top prosecutor overseeing sexual assault cases has been suspended over allegations he groped a female lawyer working for him and tried to kiss her, officers said Thursday.

The suspension marks the latest embarrassing setback for the US military as it grapples with a sexual assault crisis that has sparked calls for a radical overhaul of its judicial system.

The allegations were first reported by the Stars and Stripes newspaper and confirmed to AFP by military officers, who spoke on condition of anonymity.

The allegations involve Lieutenant Colonel Joseph Morse, who supervises the army's special victim prosecutors that handle sexual assault, domestic abuse and crimes against children cases.

The female army lawyer has alleged Morse groped her and attempted to kiss her against her will.

The alleged incident took place in 2011 in a hotel room at a sexual assault legal conference in Alexandria, Virginia, officials said, before Morse was named to his current job.

Morse also served as the lead prosecutor in the criminal case against Staff Sergeant Robert Bales, who pleaded guilty to a mass murder of Afghan civilians in 2012.

No legal charges have been filed in the case, which remains under investigation, officials said.

"We can confirm that this matter is currently under investigation and that the individual in question has been suspended from duties, pending the outcome of the investigation," a defense official said.

"Given that this is still an open case, we are precluded from providing any additional information at this point," said the official, who spoke on condition of anonymity.

Reports of sexual assaults in the US military jumped 60 percent last year, though officials say the surge shows victims have more confidence their cases will be taken seriously.

About 5,400 cases of sexual assault were reported in fiscal year 2013, compared to 3,374 reports in 2012, according to the Pentagon.

There have been a spate of high-profile sexual assault cases in the past two years, leading to a series of initiatives and prompting President Barack Obama to express outrage over the problem.

Lawmakers were due to vote Thursday on proposals to strip military commanders of authority to decide if sexual assault and some other criminal cases should go to trial.