President Felipe Calderon says Mexico's local police forces have been battered during the country's nearly five-year offensive against drug cartels.
Calderon says drug gangs corrupted and infiltrated many municipal police forces, and that success in the drug war won't come until local police and prosecutors' offices are cleaned up and made more effective.
Calderon says local police in the violence-wracked northern border state of Tamaulipas have basically been replaced by the armed forces.
Calderon spoke Wednesday, the same day the Defense Department said that soldiers killed four suspects in a gunfight in the western state of Nayarit.
Nayarit has been the scene of cartel turf battles.