Migrants Were Locked Behind Bars During Deadly Mexico Fire, Witnesses Say

Migrants were locked in a cell as a blaze spread killing 39 people at a detention center in Mexico, witnesses and a survivor said on Wednesday, as Mexico's president vowed to bring to justice those responsible.

An investigation is underway to determine what happened Monday at the center in the northern border city of Ciudad Juarez, which President Andres Manuel Lopez Obrador said employed staff from the government's National Migration Institute (INM) as well as from a private contractor.

"There'll be no attempt to hide the facts, no attempt to cover for anyone," he told a news conference in Mexico city.

All the victims were male, and Mexico's government is under pressure to find out why they died after officials said the women migrants at the center were successfully evacuated.

A short video circulating on social media on Tuesday - appearing to be security footage from inside the center during the blaze - showed men kicking on the bars of a locked door as their cell filled with smoke.

Three uniformed people can be seen walking past without trying to open the door. Interior Minister Adan Augusto Lopez later appeared to confirm the video's veracity to Mexican media.

A man who survived the fire, a paramedic and a security official in the government of Chihuahua state, where Ciudad Juarez is located, all said the cell door where the men were being held remained locked as the fire and smoke spread.

It was not until rescuers arrived that the door was opened, they said. It remains unclear how much time passed between the fire being set and the door being opened.

The survivor, who was being fed oxygen through his nose for smoke inhalation and asked not to be named out of fear of repercussions from migration authorities, confirmed the information in a voice message sent from his hospital bed.

Authorities believe the fire, which killed mostly men from Guatemala and other Central American countries, was started by migrants setting alight mattresses in an act of protest when they discovered they would be deported.

Lopez Obrador said the fire began around 9:30 p.m.

Rescue Team Ciudad Juarez, a private paramedic service, reached the building at 10:05 p.m. and found men in military attire pulling people out of the men's unit, said a member of the group who was on site.

The victims had all been extracted from the building by 11:37 p.m., said the source, who declined to be named.

Outside a hospital in Ciudad Juarez, which sits across the border from El Paso, Texas, family members anxiously waited for news of their loved ones who had been injured in the fire.

Migration officials on Wednesday increased the death toll to 39, saying one person had died of their injuries.

The fire, one of the deadliest migrant tragedies in years, occurred as the U.S. and Mexico are battling to cope with record levels of border crossings at their shared frontier.

Foreign Minister Marcelo Ebrard said on Tuesday evening that those "directly responsible" had been handed over to the attorney general's office. He provided no further details.