Houston, Texas - Six people were found dead on Sunday in a cargo train boxcar in southern Texas, US media reported.
The bodies were discovered at a rail yard near the US-Mexico border by an employee for Union Pacific, a freight-hauling railroad company, the Laredo Police Department said, according to the New York Times.
Police and the Department of Homeland Security are investigating how the individuals died, the Times said.
The identities of the victims have not yet been released.
"It's a very unfortunate event ... It was too many lives that were lost," Jose Espinoza, a public information officer with the police, said, according to CNN.
Temperatures near where the train was stopped reached 90 degrees Fahrenheit on Sunday.
NBC News reported that the medical examiner believes the victims were migrants from either Mexico or Honduras, though this has not been officially confirmed.
There have been several incidents of migrants being found dead in trains or trucks near the US-Mexico border in the last few years.
Two migrants died after being found trapped in a train in Texas in 2023.
A year earlier, 53 migrants died after being abandoned in a scorching-hot tractor-trailer on an isolated Texas road.