A government-appointed panel largely blamed supporters of ousted Islamist President Mohamed Morsi for the death of hundreds of people when security forces dispersed a Cairo protest camp last August, one of the bloodiest days in Egypt's modern history.
The panel placed some responsibility on security forces, saying that they did not maintain proportional use of force during the clearing operation.
It also said that security forces did not give protesters enough time to leave the sit-in near the Rabaa al-Adawiya mosque in the Nasr City district of the Egyptian capital.
Security forces crushed two protest camps on Aug. 14 using live ammunition, witnesses and rights groups said, killing hundreds. Most of the deaths were in the Nasr City district.
The panel accused pro-Morsi protesters of detaining and torturing residents in the Nasr City district, and said that the protesters carried arms and shot at security forces.
But, in a departure from past official accounts, the panel said that the majority of the protesters were peaceful.