Soldiers, police, emergency officials, nearby residents and reporters were on the scene Sunday night when the a fire broke out and the truck filled with explosives went off, according to Luis Horacio de Hoyos of the Coahuila state Attorney General's Office.
The explosion occurred near the town of Sacramento.
Maximo Alberto Neri Lopez, a federal police official, said 37 people were killed and 150 were injured. He said the explosion left a 10-by-40 foot crater in the concrete.
De Hoyos said three newspaper reporters from the city of Monclova were among the dead.