A man’s body found on Monday in Bujumbura takes to 11 the number of people killed since the weekend amid an uptick of political violence in the Burundian capital.
The man, who was believed to have worked as a guard for a food shop, had his throat slit.
At least 10 people were killed at the weekend, including four civilians who died in grenade blasts.
Five others were shot dead.
Witnesses said they were members of the Imbonerakure, the ruling party’s youth wing, which helps police locate and arrest suspected armed government opponents.
Police confirmed the nine killings, but described the five as ordinary citizens instead of Imbonerakure members.
The 10th victim was the chief of a military post whose body with a bullet wound was seen by a dpa correspondent.
About 15 people were arrested after the killing, which took place in the pro-opposition Cibitoke neighbourhood.
The east African country has been in turmoil since President Pierre Nkurunziza announced in April that he would seek a third term in office, despite a constitutional two-term limit.
Nkurunziza won an election boycotted by the opposition in July.
More than 400 people have been killed in protests, clashes and assassinations, according to the UN.