The United Nations said Friday its investigators have discovered three mass graves at a northeast Congo military camp containing the bodies of 30 people who were allegedly executed by soldiers.

The corpses, including women and children, were found at a military camp in Ituri province after witnesses accused troops of killing dozens of people two months ago, U.N. spokesman Kemal Saiki said.

Saiki said the graves had been opened and the bodies would be exhumed for a team of investigators that includes U.N. human rights officials and Congolese military authorities.

It was not immediately clear what sparked the killings.

Much of Ituri province, home to dozens of powerful local militia groups, has remained lawless and violent despite peace deals to end Congo's 1998-2002 civil war. Tens of thousands of people have been killed in fighting there over the last decade.

Congo's army has been accused by rights groups and residents of rape, pillage and forcing civilians into labor.

The government is struggling to rebuild the postwar force into a unified military composed of rebels, militias and soldiers who fought against each other for years.