QUITO, Oct. 18 (Xinhua) -- At least 11 people were killed and 12 injured in a  traffic accident in Colta canton, in the central Ecuadorian province of  Chimborazo, the national emergency hotline ECU 911 reported on Monday.

In a  statement, ECU 911 said the accident occurred early Monday morning, when a  passenger bus plunged into a ravine in the Juan de Velasco Pangor district as it  traveled along the Panamericana Sur highway.

"Preliminarily  reports from rescue groups said the bus veered off the lane and overturned into  a ravine about 100 meters deep at 12:30 a.m. (local time)," ECU 911 said, adding  the vehicle was traveling between the towns of southwest Guayaquil and central  Ambato.

ECU 911  rescue units and technical personnel, aided by ambulances, deployed a joint  operation to help victims at the site, as the road was partially opened.