At least 15 people have been killed in central Burundi, local media report.
The attack on Saturday evening was in Muramvya province, where 12 people died in a similar attack in May.
According to eyewitnesses, gunmen blocked a road with large stones under cover of darkness and then shot at the vehicles.
Two minibuses were set ablaze.
Several wounded passengers were taken to hospitals.
Burundi’s interior ministry described the attack as terrorism. It is not clear who was behind it.