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.
"We have been watching the situation in this area for some time now and have a good idea of who is behind today's incident. We are in pursuit of the attackers and action will be taken against those responsible," army spokesperson Innocent Munyengango said in a statement.
He said 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 neighbouring Burundi and Democratic republic of 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 DRC.
Kagame blamed the earlier December 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, and the Rwanda National Congress, founded by a former army chief.
Speaking to reporters on Friday in Kigali, Kagame also addressed tensions with neighbouring Burundi, saying his country will never be pulled into "provocations" from Burundi.
Burundi's President Pierre Nkurunziza earlier this month called for an emergency meeting of the East African Community, accusing Rwanda of "aggression" and of harboring plotters of a failed coup in 2015.
In the letter dated December 4, Nkurunziza told Museveni who is also chairperson of the East African regional bloc that Rwanda was behind the crisis that hit Burundi in April 2015, which also saw a failed coup against Nkurunziza.
Rwanda has denied the allegations.
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