Burundi's army killed 31 suspected rebels and captured 170 others in fighting in the country's north, a military spokesman said on Monday.
The fighting, which comes amid political unrest over the president's controversial bid for a third term, has raised fears of a return to civil war in this central African country.
Military spokesman Col. Gaspard Baratuza told a news conference in northwestern Cibitoke province that six soldiers were wounded in recent fighting with suspected rebels, and that nearly 80 assorted weapons were seized.
Canesius Ndayimanisha, governor of northern Kayanza province, said that 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 by pro-Nkurunziza forces, but at least 77 people have died in sporadic protests in the capital, Bujumbura, by civilians who say Nkurunziza must go after serving the two constitutionally-allowed terms. The nation's constitutional court has ruled in the president's favor, saying he is eligible for a third term because he was chosen by lawmakers — and not popularly elected — for his first term.
The U.N. human rights chief Zeid Raad al-Hussein told the U.N. Security Council last week that "the risk to human life, and to regional stability and development, is high" as a result of escalating politically motivated violence and Burundi's history of recurring bloodshed and atrocities.