At least 42 migrants were found dead inside a tractor-trailer on Monday in San Antonio, Texas, the state's Gov. Greg Abbott said, in what appears to be one of the most deadly recent incidents of human smuggling along the U.S.-Mexico border.
Mexico's Foreign Minister Marcelo Ebrard called the suffocation of the migrants in the truck the "tragedy in Texas" on Twitter and said the local consulate was en route to the scene, though the nationalities of the victims had not been confirmed.
A U.S. official told The Associated Press that 15 others in the truck were taken to hospitals in the San Antonio area. He spoke on condition of anonymity because the information had not been authorized for public release. An official from the San Antonio fire department later said children were among those taken to hospital.
The truck was found next to railroad tracks in a remote area on the city's southern outskirts, local television station KSAT reported.
San Antonio police did not immediately respond to a request for comment.
It may be the deadliest tragedy among thousands who have died attempting to cross the U.S. border from Mexico in recent decades. Ten migrants died in 2017 after being trapped inside a truck that was parked at a Walmart in San Antonio. In 2003, 19 migrants were found in a sweltering truck southeast of San Antonio.
Big rigs emerged as a popular smuggling method in the early 1990s amid a surge in U.S. border enforcement in San Diego and El Paso, Texas, which were then the busiest corridors for illegal crossings.
Before that, people paid small fees to mom-and-pop operators to get them across a largely unguarded border. As crossing became exponentially more difficult after the 2001 terror attacks in the U.S., migrants were led through more dangerous terrain and paid thousands of dollars more.
Temperatures in San Antonio, which is about 250 kilometres from the Mexican border, swelled to a high of 39 C on Monday with high humidity.