"According to local officials, on December 25, the rebels killed 40 people in Faradje. On December 26 and 27, they attacked Doruma and the neighbouring village of Gurba, killing 89 people in Doruma and 60 people in Gurba," OCHA said in a statement.
At least 20 children and an unknown number of adults were abducted during the attacks, OCHA added.
Uganda, Congo and South Sudan launched a joint assault on LRA bases in northeast Congo on December 14 after Joseph Kony, the rebel leader, failed again to sign a peace deal to end his rebellion against the Ugandan government.
However, despite early bombing raids on the bases and initial claims of success, the offensive has so far failed to locate Kony, a self-styled mystic whose rebels are notorious for kidnapping women and children and forcing children to fight.