Twenty-one people were killed and 29 others injured Friday when a bus ran off the road and plunged into a ravine in the western Mexican state of Nayarit, authorities said.

The accident occurred around 4:00 a.m. on a stretch of highway between the towns of Puente de Chapalilla and Tequepexpan, state government spokesman Sergio Cañedo told Efe.

The bus was carrying tourists from the northern state of Chihuahua to the seaside resort of Rincon de Guayabitos, about 60 kilometers (37 miles) north of Puerto Vallarta.

Injured survivors were taken to three hospitals in Tepic, the capital of Nayarit.

State and federal police and investigators are at the crash site, along with fire rescue and personnel from the Red Cross.

Residents of a community in Chihuahua pooled their resources to charter the bus for the beach excursion, Nayarit officials said.

Schools let out in Mexico two weeks ago and the country's highways are crowded with families en route to vacation spots. EFE