An AFP photographer saw the bodies of the victims as well as those of eight alleged guerilla fighters killed by the army after the raid yesterday at May-Moya in North Kivu province.
The killings are the latest blamed on Ugandan rebels of the Allied Democratic Forces (ADF), who are accused of murdering around 400 people in nine months of massacres in and around the major eastern trading hub of Beni.
The mainly Muslim rebels attacked the military camp with automatic weapons before being driven back after several hours of fighting, a senior army officer at the scene told AFP.
Most of the ADF's victims have been hacked to death with machetes in atrocities that prompted a joint operation by the Congolese army and UN troops in December to root out the rebels, who used the then war-torn country as a base to launch an insurgency in neighboring Uganda against President Yoweri Museveni in the mid-1990s.
The local population has accused the government of President Joseph Kabila of failing to protect them and angry street protests in Beni have often turned violent.
The region's Catholic bishops have also been critical of Kinshasa, saying that "security, peace and territorial integrity do not seem to be priorities for the authorities.