QUITO, Nov. 16 (Xinhua) -- At least 13 people were killed and more than 20 others injured on Sunday after an interprovincial bus overturned on a road in the Ecuadorian province of Bolivar, according to local media.

The accident occurred at 1 p.m. local time, when the bus covering the Simiatug-Ambato route plunged off the highway into a deep ravine, media outlet Expreso reported.

Rescue teams, firefighters, police and the military were deployed on the site to respond to the emergency with the support of ambulances, it said.

The authorities have confirmed that among the fatalities are children and adults belonging to three families, whose bodies were taken to the morgue in the city of Guaranda, Bolivar.

The injured have been transferred to several hospitals to receive medical treatment.

Traffic accidents are one of the leading causes of death in Ecuador, mainly due to speeding and driver incompetence, according to authorities. ■