At least 23 people were killed and 70 were injured in Mexico City on Monday night after an overpass collapsed while a train traveled over it.

The crash took place around 10:30 p.m. on a new stretch of track created in 2012. According to The New York Times, residents were concerned about the structural integrity of the overpass after a 2017 earthquake caused cracks in the concrete. 

The city’s mayor, Claudia Sheinbaum, said children were included in the number of fatalities. 

Mexico City’s subway system is one of the busiest in the world, the Associated Press reported. 

This is not the first major incident involving the city’s subway system. In 2020, two trains collided, leaving one person dead and 41 people injured. In 2015, a train crashed into another, wounding 12 people. 

RELATED: More than 30 killed, 60 injured in train crash in Egypt 

WATCH: Moment train track collapses in Mexico City injuring dozens of people – Milenio pic.twitter.com/8LU4u1GYLC

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This is a developing story that will be updated.