A metro overpass collapsed on Monday night in Mexico City, sending the coaches of a passenger train diving to the ground and killing more than 20 people, authorities said.
At least 70 others were injured, officials said, and an unknown number remain trapped amid the debris and the twisted metal.
Mexico City Mayor Claudia Sheinbaum arrived at the crash site to coordinate the search and rescue operation and later confirmed that 23 people had died, news agency AFP reported.
Dozens of emergency workers were seen trying to rescue victims from the carriages. However, the work was later suspended because of fears of the wreckage being too unstable.