Soldiers at Fort Sill in Oklahoma have been suspended from duty pending the outcome of an investigation into a female soldier’s allegations that she was sexually assaulted, the Army post’s commanding general said.

Late last month, the soldier who was training at the post “reported that she was the victim of sexual assault involving Fort Sill cadre members,” Maj. Gen. Ken Kamper said in a statement Thursday.

The woman made a formal complaint on March 27, but it is unclear when the alleged assault took place. Kamper also didn’t say how many people are alleged to have been involved, only referring to them as members of a cadre. He said they were “suspended from their normal duties, removed from any trainee environment, and are all presumed innocent pending a full and thorough investigation.”

Kamper said the assault was “immediately reported to law enforcement” and is being investigated by the U.S. Army Criminal Investigation Command.

Fort Sill is an expansive installation about 90 miles (145 kilometers) southwest of Oklahoma City. It houses about 53,000 people, including 20,000 military and civilian staff, and is a prominent artillery training center.

During a news conference, Kamper did not directly answer a question about whether the assault was an isolated incident at the post, according to The Lawton Constitution. Fort Sill officials didn’t immediately respond to Sunday requests for comment.

Kamper said the soldier who reported the assault was quickly connected with victim services. “We’re proud of the courage she displayed in coming forward with these allegations,” he said.

The pervasiveness of sexual harassment and assault in the military became an issue of heightened national concern last year after the killing of Spc. Vanessa Guillen at an Army post in Texas.

Army investigators said Guillen, who was 20, was bludgeoned to death at Fort Hood by a fellow soldier who later killed himself. Guillen’s family has said she was sexually harassed by that soldier, but the Army has said there is no evidence of that.