At least 43 people were killed after a trailer broke loose from a truck and crashed into a passenger bus near a Mexican town on Friday.
In one of the worst traffic accidents the country has suffered in recent years, seven children were also among at least 17 people injured on a winding stretch of highway near the town of Alamo in the northern part of Veracruz state.
The victims were workers traveling from Coatzacoalcos in in the Gulf coast state to the northern border state of Coahuila, according to the authorities.
Pictures from the scene of the crash showed the side of the bus ripped open, with seats mangled by the impact and debris and luggage strewn across the road.
The vehicles were said to have been traveling in opposite directions along the highway early on Friday when the rear trailer of the truck decoupled, smashing into the bus.
After the two vehicles collided, another heavy truck traveling behind the bus ploughed into the middle of the trailer.
One local news network said the bus was carrying 70 passengers, but only had capacity for less than 60.
Mexico's President, Felipe Calderón, expressed his sadness over the crash in a message posted on his Twitter account.
"My deepest condolences for the families of those who died in the terrible accident this morning in Veracruz," he said.
Veracruz's governor, Javier Duarte, and his wife visited the accident site to oversee the rescue and recovery efforts, promising state support for victims and their families.
Thousands of people from Veracruz, Mexico's third most populous state, work in factories and farms along Mexico's border with the United States.