The Rwanda-backed rebel group M23 has denied involvement in recent massacres in eastern Congo. A report by Human Rights Watch, released Wednesday, accused M23 of killing over 140 civilians.

Despite a peace process, attacks were carried out in more than a dozen villages last month, Human Rights Watch says.

M23, a rebel group backed by Rwanda, killed at least 140 people in July in the Democratic Republic of Congo, Human Rights Watch said. Most victims are Hutu.