At least seven people were killed and 11 others injured early Monday when a bus overturned on a road in the central province of Cundinamarca, Colombian authorities said. The vehicle, with more than 30 students on board, tipped over on the road between the towns of Ubate and Zipaquira, near Bogota. Freddy Hernandez, one of the passengers, told Caracol Radio the students noticed "that from one moment to another (the vehicle) sped up" and the driver "did a lot of maneuvers." "We all began shouting, buckling our (seat)belts," Fernandez said. "I held on very hard, very strongly, when the bus began overturning and flipped I don't know how many times. We fell into a ravine," he said. "When we stopped, I released the belt and we started taking people off the bus, but there were many that it was impossible to remove." Col. Francisco Pelaez, director of the highway police, told Blu Radio that six people were pronounced dead on the scene and another person died en route to the hospital. Authorities are still trying to determine the cause of the accident.