Fighting has broken out between peacekeeping forces stationed in the Central African Republic (CAR) after a grenade was thrown and shots were fired.
Lieutenant-Colonel Pontien Hakizimana is the commander of the Burundi contingent of MISCA, which is the African-led International Support Mission to the Central African Republic.
He said his men were disarming rebels in the capital when Chadian troops from the MISCA attacked on Monday.
He told the news agency AFP that the Chadian grenade launch and gunfire prompted the Burundi troops to strike back.
"On Monday morning we intercepted six armed ex-Seleka and we disarmed them," Hakizimana said in a telephone interview from Bangui.
A group of Chadian soldiers went by on a truck and threw a grenade at the Burundians, which exploded without causing any casualties, he said.
"Then the Chadians left with the ex-Seleka, firing in all directions."
Some of his men came under fire and retaliated, wounding three Chadians, said Hakizimana.
"The Chadians soldiers came back in greater numbers in the afternoon and attacked our positions."
Chadian troops, who are part of the 3,700-strong MISCA force, are accused by the force commanders and by French troops deployed in Bangui of siding with the ex-Seleka rebels the force is supposed to disarm.
A military source in Bujumbura said relations between the Burundians and the Chadians had been strained ever since the Chadians in the MISCA had been re-deployed outside the capital and the Burundians were tasked with securing Bangui.
In addition to the 850 men deployed in CAR, Burundi also has about 5,500 men in the African Union force in Somalia and also plans to deploy a contingent in Mali.