Fifty-four mostly Central Americans were killed on Thursday when the truck they were in flipped over in southern Mexico, in one of the worst accidents involving migrants who risk their lives to reach the US.

The trailer broke open, spilling out people, when the truck crashed on a sharp curve outside the city of Tuxtla Gutierrez in the state of Chiapas, according to video footage of the aftermath and civil protection authorities.

Chiapas governor Rutilio Escandon said 49 people died at the scene, and five more while receiving medical attention. “It took a bend, and because of the weight of us people inside, we all went with it,” said a shocked-looking Guatemalan man sitting at the scene in footage broadcast on social media.

“The trailer couldn’t handle the weight of people.”

More than 100 people were inside the trailer, authorities said. Several dozen were injured and taken to hospitals in Chiapas, which borders Guatemala.

Dozens of Guatemalan migrants were named in lists of the injured published on social media.

A Reuters witness heard cries and sobs among survivors as emergency personnel rushed to the site of where the overturned truck shuddered to a halt by a highway footbridge.