At least 23 people have been killed and dozens injured after a metro overpass collapsed in Mexico City while a train was travelling on it, officials say.
Several train carriages plunged to the ground, crushing at least one car, which was on a busy road underneath.
Children are among the dead. Rescue workers and firefighters are still searching for survivors.
Dramatic footage has emerged showing the overpass collapsing at the Olivos station on the metro’s Line 12.
Mexico City Mayor Claudia Sheinbaum said the cause of the accident was still being investigated, but it appeared a girder had given way on the overpass.
One person trapped in a car underneath the collapsed structure had been pulled out alive and taken to hospital, she said. At least 65 people were injured, and seven were in a serious condition.
Residents had reported cracks in the structure after a deadly 2017 earthquake, according to local media. Mexico’s El Universal newspaper says transport authorities made repairs following the reports.
The accident happened at around 22:00 local time on Monday (03:00 GMT). A crane was sent to the scene to stabilise the carriages amid concerns they could fall onto the road.
“We only heard a loud thunder, and everything fell apart,” 26-year-old Mariana, who survived the crash, told El Universal.
“There were many people standing and sitting in the carriage, and when the carriage fell, we went flying and hit our heads on its roof,” she described the moment of the accident.
She also said that she and other passengers were trapped among the carriage’s twisted metal before they managed to escape through a window.
One eyewitness told Mexico’s Televisa TV network: “Suddenly I saw that the structure was shaking.”
“When the dust cleared we ran… to see if we could help. There were no screams. I don’t know if they were in shock,” the witness said.
Mexico City’s metro system is one of the most used in the world, carrying tens of millions of passengers a week. In North America, only New York’s subway carries more people every day.
Yet the incident did not occur on one of the older lines, which have been through at least two major earthquakes in the past 35 years. Rather it happened on Line 12, completed as recently as October 2012.
There will be difficult questions for the mayor’s office to come about the construction of the line, including for several former mayors.
They include Mexican Foreign Minister Marcelo Ebrard, who was in office when Line 12 was unveiled and who championed the metro’s expansion.
However, those questions must wait until later. The moment now is solely about the rescue operation as Mexicans pray the number of victims does not rise any further.
Mexico City’s metro is one of the world’s busiest rapid transit systems, carrying about 1.6 billion passengers a year.
Last year, one person was killed and more than 40 injured in a collision between two metro trains in the city.
In 1975, two underground trains collided, killing 31 people.