At least 13 people have been killed in a collision between freight trains in north-western Mexico.
TV footage showed dozens of wrecked train carriages that had been burnt in a fire caused by the initial crash.
Officials said most of the victims were undocumented migrants hitching lifts on the trains, and that at least five more people had been injured.
Sinaloa's state prosecuting office said Tuesday's crash was caused by human error.
"Someone didn't change the tracks correctly," Martin Gastelum, spokesman for Sinaloa's public prosecutor's office, told Reuters news agency.
One of the trains was carrying a cargo of corn, which was scattered across the accident scene.
Mr Gastelum said there were fears the death toll could rise.
"They are still searching to see if there are bodies buried under the corn," he said.
Hundreds of migrants from Central America risk their lives to travel across Mexico by rail, hoping to cross illegally into the US.
Many hitch rides on cargo trains, sometimes falling to their deaths.