A small truck loaded with fireworks for a religious event exploded in central Mexico on Friday, killing at least nine people and injuring dozens, with one witness saying he saw "bodies flying" as people ran for cover.

The explosion took place when one firework apparently landed on the truck in the village of Jesus Tepatepec, part of the municipality of Nativitas, 125 kilometers (78 miles) east of Mexico City, a spokeswoman for the Tlaxcala state government said.

"We have preliminary information that there are nine people dead and almost 70 injured," she told AFP.

The victims were standing near the truck on a street where people were making preparations for the celebration of a patron saint when the explosion took place shortly after noon.

The injured were rushed to hospitals in the neighboring state of Puebla.

"My God, this is a tragedy," said the bishop of Tlaxcala, Francisco Moreno, visibly shaken by the scene as he surveyed the site after the explosion.

A witness said a group of 200 people were on a field where pyrotechnics were being lit when "everything began to explode."

"Many of us were able to run, but we saw bodies flying, then everything went black," Isidro Garcia Vazquez told reporters.

Witnesses said they saw a baby among the victims.

A civil protection official said rescuers were looking for bodies in a canal. The army was helping with the emergency response.

Mexicans often set off fireworks during celebrations, but accidents have happened in the past due to the mishandling of the pyrotechnics or a lack of safety measures.