The Mexican army has started registering the weapons carried by vigilantes in the western state of Michoacan, BBC reported Monday.
The registration exercise has begun nearly four months after the "self-defence groups" launched an offensive against the Knights Templar drug cartel.
The vigilantes will be allowed to keep their weapons, but will be banned from publicly carrying assault rifles.
Most of the drug cartel leaders in Michoacan state have been killed or arrested since this January.
The vigilantes began the assault on the Knights Templar cartel independently. They took over several towns before federal police and soldiers were deployed in the area, west of Mexico City.