The death toll has risen to at least 60 from clashes last week between Christian and Muslim-dominated militias in a restive Central African Republic town, an internal UN report said Wednesday.
The bloodshed was sparked in the central town of Alindao on November 15 between Christian militiamen, known as anti-Balaka, and the Union for Peace in CAR (UPC) Muslim militia.
Other sources reported an even higher death toll on Wednesday but AFP could not confirm the information.
The number of dead had previously been reported as 48, including two priests, in the latest surge of sectarian violence in the country.
Alindao's church, a convent and a camp for displaced people were torched. Pictures seen by AFP showed burnt bodies in the fire.
The town lies on a critical route traversing the south and east of the country and is in the heart of a region with numerous gold and diamond mines that have helped fuel conflict.
People affected by the fighting have fled to the south of the city, close to the village of Datoko, according to the UN report.
It said a local NGO premises had been "looted".
"We are back to square one," Najat Rochdi, coordinator of the UN Humanitarian Affairs Office in the Central African Republic (OCHA), said in a statement.
More than 50,000 people have been affected by the violence in Alindao and Batangafo to the north, OCHA said.
Three days of national mourning have been declared in the country.
One of the world's poorest nations despite a rich supply of diamonds and uranium, the CAR has struggled to recover from a 2013 civil war that erupted when President Francois Bozize, a Christian, was overthrown by mainly Muslim Seleka rebels.
In response, Christians, who account for about 80 percent of the population, organised vigilante units dubbed "anti-Balaka" in reference to a local machete.
UN Secretary General Antonio Guterres on Saturday said the latest attack was attributed to the UPC militia, which has its roots in the Seleka group.
However the UPC accused "both Muslim and Christian bandits" of being behind the incident.
"The UPC has dispatched one of its units to stop looting and violence," the group said in statement on Monday.
Alindao is a UPC stronghold and has witnessed chronic fighting in recent months that has also killed two UN soldiers and a humanitarian aid worker.