The Sudan People's Liberation Movement/Army - In Opposition, or SPLM/A-IO, condemned the attack on Monday and blamed government forces, known as the SSPDF.
"Jebel Iraq lies within a zone that is entirely under the exclusive control of the SSPDF. Consequently, full responsibility for the massacre rests with the SSPDF forces that control the area," a statement from the opposition said.
The army spokesperson told The Associated Press he couldn't comment on the incident.
A local civil rights group, the Nile Institute for the Study of Human Rights and Transitional Justice, condemned the attack and called for "effective governance and oversight in resource-rich areas."
"This horrific act represents a grave violation of the fundamental right to life and highlights the continued vulnerability of civilians in areas affected by a weak security presence and unregulated resource exploitation," the group wrote in a statement.