The attacks were targeted at villages in the provinces of Ituri and North Kivu.
The rebel group ADF, which has pledged allegiance to Islamic State (IS), is blamed for the attacks and has been repeatedly accused of violence in the area.
In a report published on Tuesday, the human rights organization Amnesty International accuses the ADF of kidnappings, recruiting child soldiers, and committing crimes against women and girls, including forced marriage and sexual violence.
"These abuses constitute war crimes and crimes against humanity," the organization writes.
