Vigilantes hacked 12 civilians to death north of Bangui as communal tensions rose ahead of a UN vote authorising force to stop the Central African Republic's descent into chaos.
On the eve of the expected adoption by the UN Security Council of a resolution giving French and African troops the go-ahead, a military source said Wednesday that Christian militiamen had attacked Muslim herders.
"Among the victims were children and a disembowelled pregnant woman," the source told AFP, adding that at least 10 other children were hospitalised in Bangui with deep gashes to heads and limbs.
A nurse there said: "It's not uncommon to see people with machete wounds. But so many at a time? We've never seen anything like this in Central Africa before."
The attack took place late Monday around 100 kilometres (60 miles) north of the capital and the victims were all from the semi-nomadic Fula tribe.
Survivors and security officials said Christian vigilantes formed to fend off marauding gangs of mostly Muslim ex-rebels were responsible for the slaughter.
Since he toppled Francois Bozize in March, Central Africa's new ruler Michel Djotodia has struggled to rein in members of the now-dissolved Seleka group that swept him to power nine months ago.
Rogue former rebels turned warlords have set up little fiefdoms and sown terror in villages, killing, looting and raping with impunity.
In Damara, east of the capital, an estimated 30,000 people have fled Seleka attacks over the past few days.
The increasingly sectarian nature of the violence has heightened international fears that the nation was on the brink of all-out civil war.
Former colonial power France has spearheaded efforts to stop the rot in a nation already among the world's poorest and now facing a humanitarian catastrophe.
The resolution it put forward is expected to be passed by the UN Security Council on Thursday.
The move will authorise the African regional force MISCA and a small French contingent to muscle in and restore stability.
France has 600 troops already in Bangui and around 350 poised to cross the Cameroonian border, while MISCA has 2,500 men on the ground and another 1,000 on the way.
Paris is Saturday holding a mini-summit on the crisis, with 40 African leaders and UN chief Ban Ki-moon due to attend.
French and US officials have warned that a genocide could be in the making if the sectarian violence that has plagued the Christian-majority country since Djotodia became its first Muslim president was allowed to further escalate.
The intervention of French troops in particular is expected to quickly scatter gangs with modest weaponry but, in the interim, communal tensions are soaring.
Bangui has become a tinderbox where people of Chadian descent and other Muslims feel threatened and fear a wave of attacks "avenging" the crimes of Seleka gunmen.
"Those Chadian dogs are going to pay," an elderly Bangui resident told an AFP reporter with a virulence that belied his quiet manner.
The Brussels-based International Crisis Group think tank warned in a briefing paper on Monday that the city was on the brink.
"The combination of religious tensions and powerless transitional authorities is the perfect recipe for further deadly clashes between local populations and the various Seleka factions, especially in Bangui," it said.
The resolution to be voted on Thursday in New York also provides for the creation of a commission to investigate human rights and an arms embargo.
It will also request a UN report on the possible transformation of MISCA into a UN peacekeeping operation.
Central Africa is surrounded by several other chronically unstable countries and has struggled with a series of coups and rebel uprisings since gaining its independence in 1960.
Its soil holds great mineral wealth but it has remained largely untapped and its nearly half of its population of 4.5 million needs assistance.
Bangui (Central African Republic) (AFP)