The United Nations said unidentified gunmen have killed at least 12 civilians, including children, in the Central African Republic where security has been deteriorating since a March coup.
The unrest comes as the U.N. Security Council plans to vote Thursday on sending additional French troops to the country to help restore order.
The U.N. said the attack took place on Monday in a community about 95 kilometers northwest of the capital, Bangui.
Amy Martin, the head of the U.N.'s humanitarian office in Bangui, said Christian militias known as "anti-balaka" appear to have targeted mostly Muslim herders. In a statement, she said it was one of a number of violent incidents in recent days.
The U.N. said an adviser to interim President Michel Djotodia blamed supporters of ousted president Francois Bozize for the attack.
France has begun efforts to boost its military presence in the CAR to about 1,000 troops. Separately, a troop contingent from the Economic Community of Central African States (ECCAS) is due to expand into an African Union-led force of 3,600 troops this month.
In March, Djotodia led a coalition of armed groups, known as Seleka, to topple President Bozize and end his 10-year rule.
Seleka, however, has since been blamed for clashes with rival militias as well as a surge of murders, rapes, robberies and auto thefts.