Of the 53 dead, twenty-two were from Mexico, seven from Guatemala and two from Honduras, Mexican Foreign Minister Marcelo Ebrard said. The rest of the migrants are still being identified.
The authorities said the tragedy appeared to be the deadliest migrant-smuggling operation in memory. Twelve people were taken to hospitals. A tractor-trailer found near Lackland Air Force Base in San Antonio contained the bodies of 46 dead.