The clashes erupted on Thursday in the Mala region around 200 kilometres north of the capital Bangui between Seleka rebels and the Christian vigilante groups known as the anti-Balaka, an official from the African peacekeeping force MISCA told AFP.
People fleeing the fighting were forced to find refuge in neighbouring areas, according to the official.
Residents told AFP by phone that Seleka fighters still occupied Mala and were committing various atrocities.
"They kill, loot, rape and steal with impunity. There is no one to protect the population from their abuses. Even the Catholic Church in Mala was attacked and those seeking refuge inside were fired upon and had to flee," said Eric Ketegaza, one of those who fled Mala.
Today, international charity Doctors Without Borders (MSF) said it would temporarily cut back its work in the country after a bloody attack on a hospital last month left 22 people dead, including three of its own workers.