Rebels raided a Burundi military camp on Tuesday night killing an unknown number of government soldiers.
The attack launched in Kiyenzi common area in Kanyosha in Bujumbura rural is said to left the army with about 20 to 50 dead soldiers.
Two rebels were killed in an attack that came on the same day Burundi was commemorating the 19th anniversary of the assassination of Archbishop Joachim Ruhuna, a former archbishop.
Colonel Gaspard Baratuza, spokesman of the Burundian army, says the forces seized a weapon from attackers and only three government soldiers were wounded.
Colonel Baratuza said the attack lasted about 30 minutes and that the army sent military patrol in the area of the attack to comb out any remaining rebels.
Kiyenzi of residents fled to the Buhonga parish in Kamesa and Gisovu areas fearing more attacks.
Since the beginning of the challenge of the third term of President Nkurunziza in April 2015, the country has witnessed rebel attacks on military positions.
There was an armed attack was conducted in mid-July in Kabarore town of Kayanza province.
31 rebels killed, 170 captured and six soldiers were wounded.
At the start of the year, Burundi’s army captured scores of gunmen and killed others in two days of clashes in the north.
As Nkurunziza pursued a third term, it looked like Burundi was resorting to the 2005 civil war as the capital was characterised by violent civilian protests.
General Leonard Ngendakumana, a rebel general, who was involved in a failed coup attempt in May, said his comrades were mobilising forces to topple Nkurunziza.
About 100 gunmen were captured by the army, according to Anselme Nsabimana, governor of Cibitoke province.
They were reportedly trained and dispatched from Congo forests to capture Bujumbura.