Fifty were found dead in a refrigerated tractor-trailer near San Antonio, Texas, on Monday night, according to local officials.
Another 16 migrants were taken to the hospital for critical care, including four children, San Antonio Fire Chief Charles Hood said at a Monday night press conference.
A majority of the migrants transported to local hospitals were too weak to get out of the truck, Hood added.
“It is our hope and prayer that the conditions of those who were transported will improve as we speak,” the fire chief said.
Three individuals were arrested in connection to the incident, San Antonio Police Department (SAPD) Chief William McManus said at the press conference.
The case was turned over to the U.S. Immigrations and Customs Enforcement (ICE) Homeland Security Investigations team for a federal investigation.
Mexican Foreign Minister Marcelo Ebrard on Tuesday said that 22 Mexicans, seven Guatemalans and two Hondurans were among the victims.
“We are in mourning. Huge tragedy. Mexico joins investigations in the US, coordinated with DHS,” he shared on Twitter, referring to the U.S. Department of Homeland Security.
Dozens of police and emergency personnel teams responded around 6 p.m. to a major road near San Antonio to find a parked tractor-trailer truck next to a set of railroad tracks.
Hood said the tractor-trailer was a refrigerated unit, but the air conditioning system was not working. The migrants inside the truck were “hot to the touch” and suffering from heat exhaustion without any available water.
Several outlets reported Monday the incident appeared to be one of the worst cases of migrant deaths at the southern border. The area
San Antonio Mayor Ron Nirenberg said at the press conference the incident was “tragic.”
“There are forty-six individuals that we know of who are no longer with us,” Nirenberg said. “Who had families, who were likely trying to find a better life. … This is nothing short of a horrific human tragedy.”
–Updated on June 28 at 10:07 a.m.