The bodies of at least 46 people have been recovered from a truck in San Antonio that was believed to be carrying migrants from Mexico to Texas. Those on board were trapped in scorching heat with no water.
Officials have confirmed that the bodies were found in a sweltering 18-wheel truck that was left next to rail tracks in a remote area on the outskirts of San Antonio on Monday.
William McManus, local Police Chief, said that a city worker made the horrific discovery after hearing a cry for help coming from the truck around 6pm,
Sixteen people were found alive inside the truck and taken to local hospitals. Those who survived were described by San Antonio Fire Chief Charles Hood as "exhausted" and "hot to the touch", he added that there were no signs of water inside the truck.
Mr Hood said: "They were suffering from heat stroke and exhaustion. "It was a refrigerated tractor-trailer, but there was no visible working AC unit on that rig."
Officials described how they found "stacks of dead bodies" but no children are thought to have been among the dead.
San Antonio Mayor Ron Nirenberg said that 46 people who had died in the back of the truck were "families who were likely trying to find a better life". He added that "this is nothing short of a horrific human tragedy".
A spokesperson for San Antonio police confirmed on Monday evening that they had three people in custody.
The temperatures in San Antonio in recent days have been scorching and climbed to 39.4C (103F) on Monday, with high humidity - the temperature inside a trailer packed with people would have exceeded this dramatically.
Mexican Foreign Minister Marcelo Ebrard said the Mexican consul was on the way to the scene in San Antonio, which is approximately 160 miles from the Mexican border.