At least 15 passengers were killed when their bus left the highway and tumbled down a steep hillside in the Pacific coast state of Nayarit early Thursday, Mexican authorities said.
The state public safety agency said rescuers were still working to remove people from the bus and said the death toll was preliminary. Some 21 passengers were injured, it said in a statement posted to its Facebook page.
The accident occurred near Tepic, the state capital.
Local media outlets reported that the bus had departed Mexico City and was bound for the border city of Tijuana.