Updated

Migrants protesting their possible deportation set fire to mattresses at an immigration detention center in northern Mexico, near the U.S. border, starting a blaze that claimed the lives of at least three dozen migrants, Mexico's president said. 

Mexico's National Institute of Migration (INM) said 38 foreign migrants died in a fire that started shortly before 10 p.m. local time on Monday, at the detention center in Ciudad Juárez, Chihuahua. Authorities originally reported 40 dead, but later said some may have been counted twice in the confusion. 

President Andrés Manuel López Obrador said the fire was started by migrants inside the facility who were protesting after learning they would be deported. 

"They never imagined that this would cause this terrible misfortune," López Obrador said, adding that the director of INM was on the scene. 

Images from the scene showed rows of bodies lying under shimmery silver sheets outside the facility in Ciudad Juarez, across from El Paso, Texas. Ambulances, firefighters and vans from the morgue could also be seen.

INM said 68 men from Central and South America were staying at the facility. Of these, 29 more migrants were injured in the fire and were transported in delicate to serious condition to four local hospitals for care.

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Fire at the National Migration Institute (INM) building, in Ciudad Juarez

Mexican authorities and firefighters remove injured migrants, mostly Venezuelans, from inside the National Migration Institute (INM) building during a fire, in Ciudad Juarez, Mexico on March 27, 2023. (Reuters/Jose Luis Gonzalez)

The agency said a complaint has been filed with the proper authorities to begin investigating the incident. Mexico's National Human Rights Commission (CNDH) was given a hearing to intervene in legal proceedings and to safeguard foreign migrants. 

INM said it will assist in legal investigations "in order to clarify these unfortunate facts." 

"The National Institute of Migration strongly rejects the acts that led to this tragedy," the agency said, without specifying which "acts" it was referring to.

Ciudad Juarez is a major crossing point for migrants entering the United States. Its shelters are full of migrants waiting for opportunities to cross or who have requested asylum in the United States and are waiting out the process.

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Fire at the National Migration Institute (INM) building, in Ciudad Juarez

Ambulances, firefighters and vans from the morgue could be seen responding to the fire at a migrant detention facility in Ciudad Juarez, Mexico. (Reuters/Jose Luis Gonzalez)

A local newspaper, Diario de Juárez, reported that the fire began in the men's area of the detention facility and that all the victims are male. 

The cause of the fire remains unknown and is being investigated by Mexico's attorney general's office, according to media reports. 

Map of Mexico migrant fire deaths

Map shows the location of a facility in Ciudad Juarez, Mexico, where dozens of migrants were killed in a fire, Mexican officials said Tuesday. (Fox News)

This tragedy near the U.S. border comes as dual border hearings are scheduled on Capitol Hill Tuesday.

Homeland Security Secretary Alejandro Mayorkas will testify in an oversight hearing conducted by the Senate Judiciary Committee at 10 a.m.

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Migrant reacts to injured husband

Viangly, a Venezuelan migrant, reacts outside an ambulance carrying her injured husband Eduard Caraballo while authorities and firefighters remove injured migrants from the National Migration Institute building in Ciudad Juarez. (Reuters/Jose Luis Gonzalez)

At the same time, the House Committee on Homeland Security Subcommittee on Oversight, Investigations, and Accountability will hold a hearing entitled, "Biden’s Growing Border Crisis: Death, Drugs, and Disorder on the Northern Border."

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House lawmakers will hear from National Border Patrol Council President Brandon Judd and others who will speak about illegal immigration across the U.S.-Canada border, which is the longest international border between two countries in the world.

The Associated Press contributed to this report.