Witnesses in Bambari, a town 236 miles northwest of Bangui, said an initial attack early on Monday by mainly Christian militia just outside the town led to waves of reprisals by Muslim youths.
Bambari sits on a fault line that has emerged across the country, where over a year of violence has killed thousands and forced a million from their homes.
Ibrahim Alawad, a witness in Bambari, said he had counted at least 22 bodies in a village about four miles from the town after the initial attack by militia, known as 'anti-Balaka'.
"Some had been cut to pieces, some had their hearts cut out," he said. "After that the youth of the Muslim area went there. They killed about 10 anti-Balaka."