An anonymous emergency telephone call on Friday led authorities to halt a train that contained a group of "suffocating" migrants, two of whom were dead, police in Texas said.
The US Border Patrol stopped the train east of Knippa, a small community in southern Texas near the city of San Antonio, police said.
"Two of the immigrants were pronounced deceased."
Police said that Union Pacific, a freight-hauling railroad company, "will lead the investigation."
Temperatures near where the train was stopped reached 87 degrees Fahrenheit (30 degrees Celsius) in the late afternoon, according to KSAT.com, an affiliate of ABC TV in San Antonio.
