President Biden on Tuesday hit out at what he called "political grandstanding" as critics blamed his administration’s immigration policies for the deaths of at least 49 migrants in a truck in San Antonio, Texas.

Biden issued a statement after at least 50 migrants died in the incident, in which dozens of migrants were discovered in an abandoned tractor-trailer in the extreme Texas heat. It was believed to be part of a human smuggling operation.

BORDER PATROL UNION SAYS BIDEN ADMIN ‘MUST ACCEPT RESPONSIBILITY’ AFTER DOZENS OF MIGRANTS KILLED IN TRAILER 

Texas Migrant Deaths truck

June 27, 2022: An ambulance leaves the scene where police said dozens of people were found dead in a semitrailer in a remote area in southwestern San Antonio.  (AP Photo/Eric Gay)

Authorities said a city worker heard a cry for help from the truck just before 6 p.m. on Monday. Victims include at least 22 from Mexico, seven from Guatemala and two from Honduras.

Biden called the loss of life "horrifying and heartbreaking."

"While we are still learning all the facts about what happened and the Department of Homeland Security has the lead for the investigation, initial reports are that this tragedy was caused by smugglers or human traffickers who have no regard for the lives they endanger and exploit to make a profit," he said.

Biden said that the tragedy "underscores the need to go after the multi-billion dollar criminal smuggling industry preying on migrants and leading to far too many innocent deaths." He noted a recent initiative to target smugglers in the region that was announced at the Summit of the Americas. He said that 2,400 arrests have been made in three months and the effort will "intensify."

The news of the deaths had immediately sparked criticism from former officials and Republican lawmakers who linked the deaths to the Biden administration’s liberal immigration policies, which they sat have encouraged migrants to flood to the border. May saw a historic high of over 239,000 migrant encounters at the border.

 "Add 46 to the Biden/Harris/Mayorkas/Garland death toll. Not one word from any of them about enforcing our laws & securing our border," the National Border Patrol Council said in a tweet. "This administration & its policies are the single biggest factor driving the criminal chaos on the border, and they must accept responsibility."

TEXAS GOV. ABBOTT LASHES OUT AFTER 46 MIGRANTS FOUND DEAD IN TRACTOR TRAILER 

"These deaths are on Biden," Texas Gov. Greg Abbott tweeted. "They are a result of his deadly open border policies. They show the deadly consequences of his refusal to enforce the law."

"This tragic loss of life can be attributed to the Biden Admin open borders policies," former Homeland Security Secretary Chad Wolf said. "Nothing is compassionate about policies encouraging smugglers and traffickers to treat people like cargo. We need to enforce our laws to prevent these tragedies."

Lawmakers in the House, meanwhile, called on Homeland Security Secretary Alejandro Mayorkas to resign over the incident.

Migrants found dead in Texas trailer

June 27, 2022: Police and other first responders work the scene in San Antonio after dozens of migrants were discovered in an abandoned tractor-trailer in the extreme Texas heat. (AP Photo/Eric Gay)

But Biden pushed back against what he called "political grandstanding" from his critics.

"Exploiting vulnerable individuals for profit is shameful, as is political grandstanding around tragedy, and my Administration will continue to do everything possible to stop human smugglers and traffickers from taking advantage of people who are seeking to enter the United States between ports of entry," he said.

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The Biden administration has rolled back a number of Trump-era policies such as border wall construction and the Migrant Protection Protocols (MPP). It has attempted to end the Title 42 public health order expulsions implemented due to the COVID-19 pandemic, but has so far been stopped by a federal judge.

It was dealt a blow earlier this month when a judge blocked the implementation of narrowed Immigration and Customs Enforcement (ICE) priorities that restrict agents to arresting and deporting only those deemed a threat to border security, public safety or national security.

Fox News' Griff Jenkins and The Associated Press contributed to this report.