"The attack took place Saturday night and unfortunately we have just lost six civilians," said Augustin Kapupa, an official in Matembo where the first attack took place.
Kapupa blamed the attack on the Allied Democratic Forces, ADF, historically a Ugandan Muslim majority rebel coalition which established itself in eastern DRC in 1995. Its adherents have since killed thousands of civilians.
The group, one of the deadliest militias in the strife-torn area, pledged allegiance to the Islamic State group in 2019.
"After the ADF killings in Matembo, they came to us in Sayo, leaving us to mourn five dead," said local elder Antoine Kambale.
Beni official Makofi Bukuku said the death toll in Sayo could still increase, with the rebels still in the area. He said he had hoped that the national armed forces in the area, as well as Ugandan troops and a MONUSCO U.N. peacekeeping presence, would have been enough to ward off repeated danger.
"Since the beginning of the year we have only recorded deaths and kidnappings," Bukuku said, adding, "in less than three months, there have been more than 180 victims."
The attacks were claimed by the Islamic State group.
Matembo civil society leader Germain Kathemika said the local population had been warning the army of the dangers posed by the rebels' presence in the area for the past three weeks.
In late 2021, the Ugandan and DRC armies launched a joint military operation against the ADF, but they have failed to stop their attacks.
The Congolese armed forces did not immediately comment.