The attack is the latest in a series of acts of violence in the bloody conflict in eastern Congo-Kinshasa, also known as the Democratic Republic of Congo.
The killing is said to have taken place in connection with the M23 taking over the town of Kishishe.
The information that a massacre took place is supported by several credible sources, according to the Reuters news agency.
Demonstrations
Thousands of Congolese in the cities of Goma and Bukavu took to the streets and protested against the deteriorating security situation in the country.
A spokesperson for the UN peacekeeping forces on the ground has now requested an investigation into the incident in Kishishe.
In October, Rwanda's ambassador was forced to leave the country in connection with M23 taking over the town of Kiwinja in eastern Congo-Kinshasa.
Rwanda is accused by both Congo-Kinshasa's leadership and UN experts of supporting the rebels.
Something that is denied by Rwanda.