At least 18 people were killed and 25 others injured in a passenger bus accident in the Sucua canton of the Amazonian province of Morona Santiago in southern Ecuador, the Integrated Security Service ECU 911 has reported.The accident occurred on Saturday night in Huambi, when the bus covering the Macas-Loja route veered off its lane and overturned, the agency said on Sunday in a statement."The bodies were transferred to the Sucua morgue," it said, adding that the 25 injured people, including minors and adults, were taken to various local hospitals.Immediate assistance was activated with personnel from various relief institutions and fire department rescue units heading to the scene, Xinhua news agency reported.Members of the Traffic Accident Investigation Service and Criminalistics were also on hand to carry out procedures for this type of accident.