Dozens found dead in trailer in US state of Texas

At least 46 migrants have been found dead inside a tractor-trailer in San Antonio city, Texas, US officials said, in what appears to be one of the most deadly recent incidents of human smuggling along the US-Mexico border.

Mexico's Foreign Minister Marcelo Ebrard called the suffocation of the migrants on Monday 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 local fire department official said there were 46 people dead, adding 16 people including 12 adults and four children were transported to the hospital. The official said the patients were hot to the touch and were suffering from exhaustion. 

Police said three people were detained. 

Immigration policies under fire

The truck was found next to railroad tracks in a remote area on the city's southern outskirts, San Antonio's KSAT television reported.

There have been a record number of migrant crossings at the US-Mexico border in recent months, which has sparked criticisms of the immigration policies of US President Joe Biden, a Democrat.

Texas Governor Greg Abbott placed the blame for the deaths on Biden's policies on Twitter, saying they "show the deadly consequences of his refusal to enforce the law."

Temperatures in San Antonio, which is about 250 km from the Mexican border, swelled to a high of 39.4 degrees Celsius on Monday with high humidity.

Heat poses a serious danger, particularly when temperatures can rise severely inside vehicles.

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.