The United Nations condemned on Sunday a wave of “brutal” sexual attacks on women and girls in the northern town of Bentiu in South Sudan that took place in what it described as a government controlled area of the region.

On Friday, the aid agency Medecins Sans Frontieres (MSF) said that unknown gunmen have raped 125 women during a 10-day spree of violence in Bentiu, but local officials disputed the report.

South Sudan has suffered a wrenching five-year civil war and, despite a fragile peace accord signed two months ago by the government and rebel groups, remains riven with ethnic grievances and awash with weapons. Civilians from rival groups bear the brunt of the violence and cycle of revenge.

The U.N. mission in South Sudan (UNMISS) said approximately 125 women and girls have sought medical treatment after having been raped or sexually assaulted as they walked along roads near Nhialdu and Guit on their way to Bentiu and that victims reported the attacks as having been carried out by young men in civilian clothing or military uniforms. They were also beaten and robbed, it said.

“The violent assaults happened in a Government-controlled area,” David Shearer, the head of the U.N. mission, said in a statement. “UNMISS peacekeepers have immediately sent patrols to the area to provide a protective presence and our human rights team has launched an investigation to identify the perpetrators.”

Shearer added, “the mission is also urging armed forces in the area to guarantee command and control over their troops to ensure rogue elements within their ranks are not involved in these criminal acts.”