MEXICO CITY (AP) — A migrant from Ecuador died and 10 others from Colombia and Guatemala were injured in an crash that occurred while they were being taken for processing in a van operated by Mexico's immigration agency, authorities said Saturday.

Mexico’s National Migration Institute said the van was involved in a collision with a bus in the the city of Mexicali, across the border from Calexico, California.

The institute said that eight injured migrants from Colombia and two from Guatemala had been taken to hospitals for treatment.

The drivers of the van and the bus involved in Friday's crash, which happened after the migrants had been detained along the border, were also injured.

The institute didn't release the name of the 36-year-old Ecuadorian killed in the crash. A photo supplied by the agency showed the van crushed up against a utility pole.

It was the latest in a series of deaths amid an upsurge in the number of migrants heading toward the U.S. border.

On Friday, two Mexican migrants were fatally shot on the Mexican side of the border and three others suffered gunshot wounds, the Migration Institute said.

Rescue services found a group of 14 Mexican nationals at dawn on Cuchuma Hill near Tecate, a city between Mexicali and Tijuana.

The cause of the shooting wasn't known, but migrant crossings often involve agreements with local cartels for right of passage. Migrants are sometimes shot if their smuggler is working for a rival gang or if they haven’t paid passage rights. Migrants are also often robbed by roving gangs of thieves and kidnappers in border areas.

And on Thursday in the southern state of Chiapas on the border with Guatemala, a truck flipped over on the highway, killing two Central American migrants and injuring another 27.

The Migration Institute said Friday that 52 migrants were traveling in an overcrowded dump truck when the driver lost control and overturned. The injured, including six children, were transported to hospital, where they were all granted legal cards of asylum, as victims of a crime on Mexican territory.

On Wednesday, two Central American migrants died after trying to board a moving train in the state of Coahuila near the Texas border.