Jermaine Carelse from the City of Cape Town fire and rescue services said they attended to the bus attack before moving to the burning truck.
"This morning, just before 7.50, the city's fire and rescue services responded to a bus alight in Govan Mbeki Road, Philippi. Three firefighting appliances with 12 staff members were dispatched," he said. "Upon arrival it was found that in addition to the Golden Arrow bus, a truck was alight as well.
"The bus fire has been extinguished and the fire crews are proceeding under SAPS and metro police escort to the truck."
No injuries have been reported.
Carelse later said that the truck had been destroyed by the fire.
Protesters are angry about service delivery and the growing crime epidemic on the Cape Flats.