An Army captain who says she was sexually assaulted by a general has testified that twice during their three-year affair they got into arguments that ended with him forcing her to perform oral sex.

The woman testified Friday that the assaults happened in Afghanistan in late 2011 as she grew more unhappy despondent in her relationship with Brig. Gen. Jeffrey A. Sinclair. She says one assault happened in her office and the second one occurred in the general's office several days later.

Sinclair is believed to be the highest-ranking U.S. military officer ever court-martialed on sexual assault charges and faces up to life in prison if convicted.

The defense will cross-examine the woman Monday. They say they will challenge the woman's credibility.