The Mexican army said it has discovered an auto shop used to bulletproof vehicles for drug gangs.

The army says it arrested 10 people and confiscated 10 trucks of SUVs that were being bulletproofed, as well a six other vehicles in the warehouse in the northern state of Sinaloa.

The army's late-Monday statement does not say which cartel managed the shop, but it was in the home state of Joaquin Guzman, who is known as "El Chapo."

In border states such as Tamaulipas, soldiers have raided similar bulletproofing auto shops and found freight trucks completely covered in steel.

The army's operation in Sinaloa took place Sunday.