Nearly 70 men who had been locked inside an immigration facility in northern Mexico were killed or injured in a fire Monday night. It’s one of the deadliest incidents ever to occur at an immigration detention center in Mexico.

Images of the scene in Ciudad Juarez, across the border from El Paso, Texas, showed bodies covered with shiny foil blankets lined up outside the burning building. As of Wednesday, at least 40 of the 58 men who had been locked in the cell were confirmed dead, dozens others were injured. Guatemalan officials confirmed that 28 of those killed were from that country. Most of the other victims were from Honduras, Venezuela and El Salvador.

Mexico’s President Andrés Manuel López Obrador said during this Tuesday morning press conference that some of the men detained at the facility lit mattresses on fire in protest after learning they would be deported.

But a video circulated on social media from inside the detention facility seems to show immigration officials ignoring migrants as smoke fills the room and they attempt to escape their cell without success.

Advocacy groups are calling for a criminal investigation into the fire, and for authorities to be held accountable for the deaths of those in their care.

“These are people who were apprehended by Mexican authorities and were being detained in this detention center and had committed no crime, and who now have died because of the negligence of the Mexican government in the way it manages these centers, and its lack of effort to protect these people when there was a fire at the detention center,” said Tyler Mattiace, the Mexico researcher with Human Rights Watch.

“What we’re calling for is for Mexico’s attorney general to open a criminal investigation here,” he said. “That’s the first step.”

Mattiace and others, however, also point to increasingly harsh immigration policies in both Mexico and the United States as creating the conditions for such a tragedy.

“The U.S. for years has been pushing Mexico to do its dirty work in terms of immigration enforcement. And the current Mexican government has stepped up in a big way its efforts to do that,” Mattiace said.

For years now, the number of migrants waiting in Ciudad Juarez and other Mexican border cities has risen sharply because of U.S. policies under the Trump and Biden administration that have made it more difficult for people to seek asylum at the border and have expelled migrants who enter outside the U.S. outside of ports of entry back into Mexico.

Last year, Mexico detained a record-breaking 450,000 migrants — often holding them in unsanitary and crowded conditions — in order to prevent them from reaching the U.S. border, Mattiace said.

This tragedy is evidence that immigration policies based predominantly on enforcement are “clearly ineffective and are deadly,” he said.

“The Biden administration should be rethinking the way it is approaching immigration to reduce the danger that many people are forced to expose themselves to in order to find safety abroad,” he said.

A citizen advisory council for Mexico’s immigration agency has also called for major reforms, including an end to detention.

In a news release Tuesday it called on Mexico’s president to stop calling detention centers “shelters,” for a thorough investigation of this case, and for immigration officials to review safety protocols and stop criminalizing migrants. It also asked Congress to carry out “an urgent legislative analysis to establish alternatives to migrant detention.”

On Tuesday afternoon, Mexico’s immigration agency said it would cooperate with Mexico’s attorney general and human rights commission in their investigations into the fire, confirming that at least 40 migrants had died and 28 others were seriously hurt in the fire.