The bodies of at least 46 people believed to be migrants were found on Monday in and around an abandoned tractor-trailer on the outskirts of San Antonio, a major city in south-central Texas, officials said. Officials said a city worker had discovered the 18-wheeler that carried up to 100 individuals abandoned at the scene after hearing cries for help. Nearly two dozen Mexicans, seven Guatemalans and two Hondurans were among the dead. Those found alive, including four children, were taken to hospital but suffered apparent heat exhaustion and dehydration. More of the surviving migrants later died at a Texas hospital Tuesday morning according to officials, bringing the total death toll to 50. Three later died at Baptist Medical Center, a spokeswoman confirmed. Where the 50th victim died was not immediately clear.
The survivors were "hot to the touch" and suffering from heat stroke and heat exhaustion.
Authorities are working to confirm the nationalities of remaining victims.
Texas Gov. Greg Abbott blamed President Joe Biden and his immigration policies for the incident.
In a tweet, Abbott said Monday evening’s discovery rests squarely on Biden. “At least 42 people found dead inside Truck carrying migrants in Texas. These deaths are on Biden,” Abbott said.
Mexico’s president while reacting to the unfortunate development said “poverty and desperation” led to the deaths of the migrants people.
Andres Manuel Lopez Obrador blamed trafficking and "a lack of control" at the border - the worst case of migrant deaths due to smuggling in the US.
Speaking at his daily briefing, Mr Lopez Obrador, better known as Amlo, called the discovery a "tremendous tragedy", and said Mexico would work to repatriate the remains of its citizens.
This and other migrant deaths were due to the "poverty and desperation of our Central American brothers, and of Mexicans," he said, adding: "It happens because there is trafficking of people and a lack of control, in this case at the Mexican-US border, but also in the US interior".
The discovery in San Antonio led to the arrest of three people. It comes as authorities are struggling with a migration surge at the southern border.