An elevated train derailed in Mexico City after a concrete overpass it was crossing collapsed Monday night. At least 20 people were killed and 49 people were injured and transferred to several nearby hospitals, according to government officials.

Phots posted online show two train cars dangling precariously from the elevated track. The yellow and orange cars crashed into one another as the overpass collapsed, leaving them suspended at a V-shaped angle.

The La Jornada newspaper reported the crash occurred at roughly 10:25 p.m.

Claudia Sheinbaum, the Mexico City mayor, continued to update the public throughout the night and early morning following the crash. The total tally of those dead continued to rise overnight.

The derailment occurred on Line 12 of the subway system at Olivos Station, according to Mexico’s civil protection agency. Shortly after the crash, Mexico City’s metro service warned the public to stay away from the area.

Line 12 will remain closed as emergency responders continue to work in the crash site, likely slowing down one of the world’s busiest metro systems.

Given the tenuous position of the wreckage, recovery efforts were temporarily halted overnight so a crane could stabilize the site for emergency responders.

Sheinbaum said on social media that a full structural review of the entire subway line and investigation into the cause of the crash will be ordered.

The city’s subway system was the site of another crash in March 2020. Two trains collided with each other, killing one man and injuring 41 people, according to the Associated Press.

This is a developing story. Some facts reported by the media may later turn out to be wrong. We will focus on reports from police officials and other authorities, credible news outlets and reporters who are at the scene, and we will update as the situation develops.