A former drill sergeant at a Missouri Army post is accused of sexually assaulting several female soldiers during the past three years, including at least one while he was deployed in Afghanistan.

Staff Sgt. Angel M. Sanchez appeared at a pretrial hearing at Fort Leonard Wood on Wednesday and could face a court-martial later this year, the Washington Post reported.

Military prosecutors allege that, among other things, Sanchez used his position as a drill sergeant on the Army post to threaten some of the women he's accused of assaulting. He is accused of sexually assaulting four women and assaulting eight others by touching them inappropriately, Tiffany Wood, a Fort Leonard Wood spokeswoman, told the newspaper.

Sanchez served one tour each in Iraq and Afghanistan, earning a Bronze Star. He arrived at the Missouri post in August and trained new soldiers with the 14th Military Police Brigade, but he no longer performs drill-sergeant duty and now works an office job with his unit, Wood said.

Several of the women Sanchez is accused of attacking testified at Wednesday's hearing.

Sanchez's lawyer, Ernesto Gapasin, told the paper "there are a lot of issues with the credibility of the witnesses and the government's case." He said Sanchez was told of the charges by his commanding officer on May 13.

According to the charging documents, Sanchez's alleged crimes date back to his year in Afghanistan, which lasted from March 2011 until March 2012. Prosecutors allege that during that time, Sanchez raped a female service member in a temporary housing unit for women on the base. He is also accused of sexually harassing female soldiers during that time.

Prosecutors also allege that Sanchez committed several sexual assaults at Fort Leonard Wood between Sept. 17 and Jan. 31 of last year. In one attack, Sanchez made a soldier fear she would be kicked out of the Army if she didn't engage in sexual acts, the charging documents state. He forced her to perform oral sex on him in an office he shared with other drill sergeants, military officials said.

Sexual assault has been a front-burner issue for the Pentagon, Congress and the White House over the past year, triggering Capitol Hill hearings and persistent questions about how effectively the military was preventing and prosecuting assaults and how well it was treating the victims. Fueling outrage have been high-profile assault cases and arrests, including incidents involving senior commanders, sexual assault prevention officers and military trainers.

At the same time, the military has long struggled to get victims to report sexual assault in a stern military culture that emphasizes rank, loyalty and toughness. Some victims have complained they were afraid to report assaults to ranking officers for fear of retribution, or said that their initial complaints were rebuffed or ignored.

The Senate passed a bill in March that would remove military commanders' ability to overturn sexual assault convictions, provide alleged victims with an independent lawyer, and require convicted military members to be sentenced to a dishonorable discharge, at the minimum. The House hasn't voted on the bill.