A highway collision between a passenger bus and a semitrailer in northern Mexico left at least 16 dead and 22 injured Thursday.

The accident occurred outside the border town of Sonoyta, across from Arizona. The highway parallels the U.S.-Mexico border and connects Sonoyta with San Luis Rio Colorado. The Sonora state prosecutor's office said via Twitter that six of the 22 injured were in critical condition. Photographs from the scene showed the front half of the bus demolished with the cab of the semi-buried in the first rows of seats.