The U.N. Human Rights Council said at least 40 people were reported killed since Jan. 10 in Bangui. Violence has continued since Prime Minister Nicolas Tiangeye and President Michel Djotodia agreed last week to resign.
Djotodia commanded the rebel Seleka coalition, which toppled the CAR government last year, but quickly lost control of the situation.
Conflict took on a religious tone when the anti-balaka, a Christian militia, took up arms against Seleka, a Muslim group.
John Ging, a director of operations at the U.N. Office for the Coordination of Humanitarian Affairs, told the U.N. Security Council the violence was having a direct impact on civilians.
"Ordinary people from both communities are living in fear," he said Thursday.
Categorizing the conflict as inter-communal, however, wasn't accurate because those accused of committing atrocities in CAR "are not representing their communities," he said.
Most of the population in CAR, one of the poorest nations in the world, is in need of some form of humanitarian assistance. Ging said donors, however, have provided only 6 percent of the $247 million he said is needed to address the "mega tragedy" in CAR.