Rebels in Burundi opened fire on an armoured car carrying aid workers and burnt out a second vehicle on a main lakeside road south of the capital, humanitarian staff said on Thursday. Twenty to 30 rebels laid a tree across the road near Magara, around 35kms from Bujumbura, on Wednesday and shot at the vehicle belonging to Catholic Relief Services (CRS), forcing the driver to reverse for two kms to escape. David Rothrock, CRS's Burundi director, said three of his agency's staff were in the vehicle but were uninjured in the ambush by rebels positioned in the road and on a nearby hill. An estimated 200 000 people have died in Burundi's civil war, which pits three Hutu guerrilla groups against the country's Tutsi-dominated army.