The discovery late Monday that dozens of migrants perished in a trailer while trying to cross the U.S.-Mexico border sparked outrage among lawmakers and fresh questions about the Biden administration’s border policies.

Democratic lawmakers blamed the public health directive known as Title 42, which has been used for more than two years to expel asylum-seekers, for causing migrants to turn to dangerous alternatives. The Biden administration attempted to rescind Title 42 last month, but was blocked by a federal judge.

“We need to end Title 42 and fix our broken immigration system so these unimaginable tragedies stop happening,” Rep. Jesús “Chuy” García, D-Ill., tweeted. “People fleeing violence and poverty deserve a chance at a better life.”

Rep. Joaquin Castro, D-Texas, said late Monday that he had spoken with Homeland Security Secretary Alejandro Mayorkas, whose department is working to alert the families of the victims and investigate the incident. The death toll — reportedly at least 46 people — is one of the gravest instances of migrant death in recent U.S. history.

In a press gaggle aboard Air Force One, White House Press Secretary Karine Jean-Pierre said the White House was focused on accountability for the human smugglers who brought the migrants across the border as well as broader government efforts to deter human smuggling networks.

“The fact of the matter is the border is closed,” Jean-Pierre said, “which is in part why you see people trying to make this dangerous journey using smuggling networks.”

Homeland Security Investigations, the investigative arm of DHS looking into the incident, said Tuesday morning that it would “continue to address the serious public safety threat posed by human smuggling organizations and their reckless disregard for the health and safety of those smuggled.”

Democratic lawmakers who have pushed for immigration overhaul bills said that strict border policies like Title 42 compound an outdated immigration system that includes few legal pathways for migrants from regions like Central America.

“These people were young, innocent souls just seeking a better life here in America,” Sen. Ben Ray Luján, D-N.M., tweeted. “This is yet another horrific reminder that punitive border policies like Title 42 upend an already broken system — it needs to end.”

Republicans, meanwhile, blamed the deaths on the Biden administration’s immigration policies, arguing that President Joe Biden’s departure from stringent Trump-era border measures encourages migrants to take deadly risks.

“These deaths are on Biden,” Texas Republican 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.”

The GOP response echoes similar concerns raised in the spring of 2021, when Biden’s decision to exempt unaccompanied children from Title 42 prompted thousands to cross the border, forcing the government to scramble to arrange proper care for them.

“This is the result of the inhumanity that comes with incentivizing this type of crisis at the border,” Rep. Mike Garcia, R-Calif., tweeted. “The US must secure the border before more lives are lost.”