At least two Rwandan civilians were killed and eight injured when attackers set fire to three passenger vehicles in the southern Nyamagabe district, which borders Burundi, said a Rwandan army official.
Army spokesman Innocent Munyengango said in a statement that the army is pursuing the attackers who retreated into Nyungwe Forest, a mountain rainforest area that is home to wild chimpanzees.
The attack highlights continuing tensions between Rwanda and neighboring Burundi and Congo.
Just two days earlier, President Paul Kagame said two or three Rwandan army soldiers were killed by rebels who had crossed the border from Congo.
Kagame blamed the earlier Dec. 9 attack in the country's western Rubavu district on the Forces for the Liberation of Rwanda, which has links to perpetrators of the 1994 genocide.