Authorities reported on Tuesday that at least 51 migrants had died after being locked inside a hot tractor-trailer vehicle that was discovered abandoned in Texas. Two Mexican nationals connected to the smuggling event have been accused in a US federal court.

One of the bloodiest cases of human trafficking in recent memory saw the discovery on Monday of the migrants' bodies—39 men and 12 women—on the outskirts of San Antonio, Texas.

According to court records and US officials, two suspects, Juan Francisco D'Luna-Bilbao and Juan Claudio D'Luna-Mendez, both of Mexican citizenship, have been accused of unlawfully staying in the US and having guns.

The two males were each nabbed separately after investigators followed the truck's vehicle registration to a San Antonio house that was under investigation.

A third suspect, who is thought to be a US citizen and was driving the truck, has also been apprehended and was supposed to be prosecuted, but as of Tuesday evening, a Mexican official said that he was still hospitalised.

In the suburbs of San Antonio, where temperatures climbed to a high of 39.4 Celsius, the vehicle had been left parked near to some railroad tracks. After the trailer's back door was unlocked, bodies were discovered inside the truck and scattered across a few streets, a local law enforcement official told Reuters on Tuesday.

On MSNBC, San Antonio Mayor Ron Nirenberg stated, 'It's unspeakable,' stressing that his city depends on immigrants despite a labour crisis.

“It’s a tragedy beyond explanation.”

In a statement on Tuesday, US President Joe Biden called the act 'horrifying and heartbreaking.'

The US-Mexico border has seen a record number of migrant crossings since Biden took office in January 2021. 'Exploiting vulnerable people for profit is shameful,' Biden added, pledging to crack down on multibillion-dollar illicit smuggling companies.

Officials from all three nations said that at least 27 Mexicans, three Guatemalans, and four Hondurans were thought to be among the fatalities. The nationalities of the other fatalities were not immediately known.

Four kids were among the more than a dozen survivors who were sent to local hospitals for treatment of heat exhaustion and heat stroke.

Even as immigration activists pointed fingers at his own strict policies, Texas Governor Greg Abbott blamed President Joe Biden, claiming they push desperate refugees to entrust their lives to unscrupulous smugglers.

The governor said on Twitter, 'These deaths are on Biden.'

They are the outcome of his dangerous open border policy.

They demonstrate the fatal results of his failure to uphold the law.

He stated in a statement that 'profiting from exploiting the weak is disgusting, as is political posturing around sorrow.'

The fatalities, which the president described as 'horrifying and devastating,' 'underline the need to go after the multi-billion dollar illegal smuggling business preying on migrants and causing far too many innocent deaths,' he said.

The White House boasted 2,400 arrests in the previous three months as part of an anti-smuggling strategy with Mexico and others.

According to the law enforcement officer and a US Customs and Border Protection (CBP) official informed on the inquiry, the vehicle may have been transporting roughly 100 migrants, although the precise number was still unknown.

According to a Mexican source, a CBP officer, and another US official who all asked to remain anonymous to discuss the subject, it appeared the migrants had just crossed the border and were picked up by the truck to be brought to where they would labour.

Officials reported that the bodies were found with a smelly chemical sprayed on them, a tactic some smugglers are known to employ to cover the scent of human cargo and avoid canine detection.

The migrants who are still alive will probably be allowed to enter the US in order to apply for asylum or other types of aid.

The US Marshals Service has brought into custody some prior victims of people smuggling so they may serve as witnesses.

The fatalities brought to light the difficulty Biden, a Democrat who into office promising to undo parts of his Republican predecessor Donald Trump's strict immigration policies, had in managing migrant crossings. Republicans have criticised Biden's border approach in the run-up to the November legislative midterm elections.

Due to the significant amount of trucks travelling on the I-35, which passes close to where the vehicle was discovered, common smuggling routes pass via San Antonio from the Mexican border.

More than 2 million migrants, mostly from Mexico, Guatemala, Honduras, and El Salvador, have been expelled as a result of a pandemic-era rule that has been in place since March 2020. This rule denies migrants the opportunity to apply for asylum but encourages repeat attempts because there are no legal repercussions for being caught. Due to increased expenses of transporting them home, deteriorating diplomatic ties, and other factors, people from other nations—most notably Cuba, Nicaragua, and Colombia—are subject to Title 42 jurisdiction less frequently.