The deaths of two migrants in a train car in a small Texas town in Uvalde County marks the latest tragedy to hit the southern border amid a historic migrant crisis – a crisis being facilitated by human smugglers, who will often put migrants in deadly situations.

The Uvalde Police Department received a 911 call Friday afternoon saying there were "numerous" migrants "suffocating" in a train car. Border Patrol had been informed and stopped the car two to three miles east of Knippa, Texas. The incident is suspected to be related to human smuggling, sources said. 

Officials for Union Pacific Railroad later said that 15 people were found in the rail car, two people died while four were air-lifted to San Antonio, and six were taken to nearby hospitals.

"Union Pacific is deeply saddened by this incident and the tragedies occurring at the border. We take the safety of all individuals seriously and work tirelessly with law enforcement partners to detect illegal items and people riding inside or on our rail cars. This incident is under investigation," it said.

TEXAS AUTHORITIES SAY AT LEAST 2 MIGRANTS DEAD, OVER A DOZEN INJURED AFTER SUFFOCATING IN TRAIN CAR

San Antonio migrant deaths

Law enforcement vehicles and officers photographed via helicopter investigating train cars where more than a dozen migrants were found "suffocating" near San Antonio, TX. (Credit: KENS 5 San Antonio) (KENS 5)

Homeland Security Secretary Alejandro Mayorkas said in a statement that the agency is "heartbroken to learn of yet another tragic incident of migrants taking the dangerous journey."

"I thank the Border Patrol Agents who responded to the scene and the HSI Agents who are supporting the investigation in Uvalde. We will work with the Uvalde County Sheriff’s Office to hold those responsible. Smugglers are callous and only care about making a profit," he said.

It marks the latest deadly incident at the border as authorities face a historic surge of migrants that saw over 2.4 million encounters last fiscal year and the second such tragedy within a month.

Earlier this month eight migrants died after two smuggling vessels capsized off the coast of Southern California. At least 15 migrants were on one of the boats, and eight on another. It was unclear how many made it to shore.

SEVEN MEXICAN NATIONALS AMONG THE EIGHT MIGRANTS WHO DIED AFTER SMUGGLING BOATS CAPSIZED NEAR SAN DIEGO

Seven of the deceased migrants were identified as Mexican nationals based on the identification documents they were carrying. Officials said that such boats are often overloaded and poorly maintained.

Those deaths came after a FY 2022 in which there were 856 migrant deaths at the southern border – the highest and deadliest on record. That has coincided with a record number of migrant encounters at the border. The 2.4 million seen that year exceeded the 1.7 million encountered a year before, which itself was a record.

The most deadly incident of the year came in June when 53 migrants died after being locked in a tractor-trailer in San Antonio, Texas. The dead included a 13-year-old and 14-year-old from Guatemala and two 16-year-olds from Mexico.

The truck had been carrying 73 people when it was found on June 27.

In September, nine migrants were killed in the Rio Grande as they tried to cross into the United States from Mexico, while Border Patrol agents rescued 37 others.

The same month, agents narrowly averted tragedy when they rescued a four-month-old and an 18-month-old who had been abandoned in the sweltering heat of the Arizona desert.

Meanwhile, the debate over solutions to the crisis rages on in Washington. Republicans have blamed the Biden administration for its policies that they say have encouraged migrants to surge to the southern border – specifically its moves to reduce interior enforcement and release more migrants into the interior.

San Antonio migrant deaths

Law enforcement vehicles and officers photographed via helicopter investigating train cars where more than a dozen migrants were found suffocating near San Antonio, TX. (Credit: KENS 5 San Antonio) (KENS 5)

The administration has faulted Republicans for failing to agree to border funding requests. It has also launched anti-smuggling operations and sought to expand legal pathways – including a recent humanitarian parole program – so migrants can travel into the U.S. without entering illegally.

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The latest deaths come just weeks before Title 42, which allows for the rapid expulsion of illegal migrants at the southern border due to the COVID-19 pandemic, is set to expire on May 11 along with the public health emergency. Officials have previously warned that a dramatic increase in migrant crossings can be expected when the order drops.

Fox News' Bill Melugin, Brie Stimson and The Associated Press contributed to this report.