More than 40 dead are said to have been found in a truck in South Texas, US media reports.
The people are believed to be illegal immigrants who were smuggled to the United States and around 15 survivors have been taken to hospitals in San Antonio, says an anonymous police source to the news agency AP.
How the victims died has not yet been clarified, but San Antonio and the surrounding area suffered a heat wave in June with temperatures that have almost reached record levels.