Updated

Police have found three human heads in the same small town in western Mexico where another three heads were found a day earlier.

Michoacan state prosecutors' spokesman Alejandro Arellano says the heads found Friday were left at a monument in Los Reyes, a town where "self-defense" vigilantes have clashed with drug traffickers in recent months.

Arellano says a note threatening the town's self-defense group was left near the human remains.

A message was also left Thursday but authorities wouldn't reveal its content.

Self-defense squads have been forming in recent months in Michoacan by people who say they are fighting drug cartels.

Last month, police found the bodies of two men hanging from a tree in the town of Los Reyes along with a message threatening the community's self-defense group.