Mexico City — An elevated section of the Mexico City metro collapsed and sent a subway car plunging toward a busy boulevard late Monday, killing at least 23 people and injuring about 70, city officials said. Mayor Claudia Sheinbaum said 49 of the injured were hospitalized, and that seven were in serious condition and undergoing surgery.
A crane was working to hold up one subway car left dangling on the collapsed section so that emergency workers could enter to check the car to see if anyone was still trapped.
Sheinbaum said a motorist had been pulled alive from a car that was trapped on the roadway below. Dozens of rescuers continued searching through wreckage from the collapsed, preformed concrete structure.
"There are unfortunately children among the dead," Sheinbaum said, without specifying how many.
The overpass was about 16 feet above the road in the southside borough of Tlahuac, but the train ran above a concrete median strip, which apparently lessened the casualties among motorists on the roadway below.
"A support beam gave way," Sheinbaum said, adding that the beam collapsed just as the train passed over it.
Rescue efforts were briefly interrupted at midnight because the partially dangling train was "very weak."
"We don't know if they are alive," Sheinbaum said of the people possibly trapped inside the subway car.
Mexico's prosecutor's office said it will investigate the collapse, CBS News correspondent Manuel Bojorquez reports. The U.S. National Transportation Safety Board has not been contacted by the Mexican government to assist in the investigation, CBS News transportation correspondent Errol Barnett reports.
Hundreds of police and firefighters cordoned off the scene as desperate friends and relatives of people believed to be on the trains gathered outside the security perimeter.
Oscar López, 26, was searching for his friend, Adriana Salas, 26. Six months pregnant, she was riding the subway, returning from her work as a dentist when her phone stopped answering around when the accident occurred.
"We lost contact with her at 10:50 p.m., there was literally no more contact," López said.
Adrián Loa Martínez, 46, said that his mother called him to tell him that his half-brother and sister-in-law were driving when the overpass collapsed and that beam fell onto their car.
He said that his sister-in-law was rescued and sent to a hospital, but that his half-brother José Juan Galindo was crushed and he feared he was dead. "He is down there now," he told journalists pointing toward the site.
Gisela Rioja Castro, 43, was looking for her husband, 42-year-old Miguel Ángel Espinoza. She said that her husband always takes that train after finishing work at a store, but he never got home and had stopped answering his phone. When she heard what has happened, she immediately feared the worst but has gotten no information from the authorities.
"Nobody knows anything," she said.
The collapse occurred on the newest of the Mexico City subway's lines, Line 12, which stretches far into the city's southside. Like many of the city's dozen subway lines, it runs underground through more central areas of the city of 9 million, but then runs on elevated, pre-formed concrete structures on the city's outskirts.
The collapse could represent a major blow to Mexican Foreign Relations Secretary Marcelo Ebrard, who was Mexico City's mayor from 2006 to 2012 when Line 12 was built. Questions about the quality of the construction emerged soon after he left office as mayor.
Ebrard wrote in his Twitter account, "What happened today on the Metro is a terrible tragedy."
"Of course the causes should be investigated and those responsible should be identified," he wrote. "I repeat that I am entirely at the disposition of authorities to contribute in whatever way is necessary."
The Mexico City Metro, one of the largest and busiest in the world, has had at least two serious accidents since its inauguration half a century ago.
In March of last year, a collision between two trains at the Tacubaya station left one passenger dead and injured 41 people. In 2015, a train that did not stop on time crashed into another at the Oceania station, injuring 12 people.