The prosecutor's office in Nayarit, the state where the accident occurred, said the vehicle fell some 15 meters (49.21 ft) down a ravine on Saturday night, on a highway that connects state capital Tepic and the tourist destination of Puerto Vallarta.
"From the first moment, we have worked in a coordinated manner with the various federal and state authorities to provide immediate attention to victims," the prosecutor's office said in a statement shared on Twitter.
Authorities reported that 11 women and seven men were killed. At least 11 minors have been transferred to hospitals for medical attention.