Family members of the victims are in great pain outside the Legal Medical Service, in Taltal, Antofagasta province, Chile, on Dec. 2, 2019. (Xinhua/Edgard Cross-Buchanan/AGENCIAUNO)

As many as 21 people were killed after a passenger bus plunged into a ravine in northern Chile, local authorities said Monday.

The accident, which occurred late Sunday near Taltal, a community in Antofagasta province, left another 20 people injured, Taltal prosecutor Ricardo Castro told reporters.

"We want to give the community the tranquility of knowing that we are going to carry out all the necessary investigations to determine the identity of the person or persons responsible for the incident," said Castro.

The double-decker bus had departed from the town of Antofagasta around 8:30 p.m.local time (2330 GMT) on its way to Ovalle with some 50 passengers on board.

According to reports, the bus was traveling along an alternative route to the highway in order to save time and the driver lost control of the vehicle at a point where the road slopes.

Chilean President Sebastian Pinera expressed his "deep" regret for the loss of lives in a message on Twitter.

The injured were taken to area hospitals for treatment.