Rwanda's military says a 52-year-old woman has been killed in an attack by unknown gunmen in the southwestern district of Rusizi near the Burundi border.

Rwandan military spokesman Col. Rene Ngendahimana says the attack occurred late Tuesday in the same area where gunmen killed two civilians in March and fled into Burundian territory.

Ngendahimana says eight others were injured in this latest attack.

He says it is not yet known whether the attackers came from Burundi.

Relations between Rwanda and Burundi have been strained following allegations by Burundi's government that rebels opposed to President Pierre Nkurunziza are being trained and armed in Rwanda.

Rwanda has repeatedly denied the allegations.