BAMBARI, Central African Republic (AP) — French forces in Central African Republic have fired mortars and exchanged sustained gunfire on Saturday with Muslim rebels who once controlled the country.

The substantial engagement by the French, including a Gazelle helicopter that fired a rocket, occurred in the central town of Bambari. Ex-Seleka forces crossed the bridge on the Bangui road and engaged French forces 300 meters from a bridge, said a French military officer on condition of anonymity because he is not authorized to speak to the press.

The group known as Seleka was forced from power in January nearly a year after its fighters overthrew the president. Christian militias have sprung up, saying they are seeking revenge for atrocities committed during Seleka's rule and plunging the country into sectarian violence that has left thousands dead.