At least 70 people have been hospitalized, seven of whom are in serious condition, officials added.
The train was traveling on an elevated part of the city’s rapid transit system on the newest Line 12, also known as the Golden Line, when part of the overpass collapsed onto traffic below, Mexico’s Secretariat of Risk Management and Civil Protection said.
CCTV surveillance footage shows the moment the overpass collapsed onto the street, sending up a cloud of dust and debris.
The incident happened at 10:25 p.m. local time, according to Mexico City’s Interior Minister Alfonso Suarez Del Real.
The mayor said one survivor was trapped in a vehicle beneath the rubble, but has since been freed. There were no other people trapped, she added.
Rescue efforts were temporarily suspended earlier in the night due to concerns over the stability of the subway car, which was still dangling over the road.
The Metro’s Line 12, where the accident happened, was opened in 2012. There would be an investigation into the accident, the city’s mayor said.
“Our main task is to attend to the people who are in the hospitals, to attend to the relatives of the victims who unfortunately died in this incident,” said Sheinbaum, Reuters reported.
“The Public Prosecutor’s Office will carry out all the investigations, will make all the expert reports to find out what happened in this accident on line 12 of the subway,” she added.