Over 40 persons, reportedly migrants were found dead in a truck abandoned on the outskirts of Texas.
Mexican authorities said that the nationalities of the deceased are yet to be identified.
The Associated Press reported that about 15 persons were also rushed to hospitals in San Antonio on Monday for treatment.
It is presumed to be a migrant smuggling attempt in South Texas, the publication quoting a local police officer said. San Antonio in Texas is around 250km from the US-Mexican border.
It was not immediately clear how the people died and local police are yet to comment publicly, BBC reported.
Texas's Republican Governor Greg Abbott blamed US President Joe Biden for the deaths, describing them as a 'result of his deadly open border policies.'
The truck was found next to rail tracks in a remote area on the city's southern outskirts, Reuters reported. In July 2017, ten migrants died after being transported in a tractor-trailer that was discovered by San Antonio police in a Wal-Mart parking lot.
The driver, James Matthew Bradley, Jr., was sentenced the following year to life in prison for his role in the smuggling operation.