One humanitarian aid worker was among the dozens of civilians killed following clashes between military forces in the DRC and rebels from the Alliance of Patriots for a Free and Sovereign Congo in the eastern town of Kitchanga.
Moustapha Soumare, the U.N. humanitarian coordinator for DRC, said he was concerned about growing ethnic tensions and arbitrary arrests tied to the latest violence.
"I'm very concerned that thousands of lives are again endangered," he said in a statement. "The parties to the conflict have to avoid civilian casualties at all cost, respect the civilian character of internally displaced settlements and ensure that humanitarian actors can provide much needed assistance."
The International Committee of the Red Cross expressed similar concerns this week.
The DRC government and members of the African community this year brokered an agreement aimed at putting the country on the path to peace.
Forces from the rebel March 23 Movement took control over parts of eastern DRC last year. They mutinied in 2012, complaining the DRC government wasn't upholding the terms of a previous peace deal.
Notable deaths of 2014 [PHOTOS]