A spokesman for Burundi's military says government troops killed 31 suspected rebels and captured 170 others in fighting that has raised fears of a return to civil war in this central African country.

Col. Gaspard Baratuza told a news conference in northwestern Cibitoke province that six soldiers were wounded in the fighting and that nearly 80 assorted weapons were seized.

Canesius Ndayimanisha, governor of northern Kayanza province, said suspected rebels carried out two attacks inside Burundian territory on Friday after entering the country through the dense Nyungwe forest on the Rwanda border.

Burundi has been tense since April when the ruling party nominated President Pierre Nkurunziza to be its candidate in presidential elections later this month.

Unrest boiled over into a military coup in May that was quickly put down.