Growing tension between Mexican police and vigilantes who have challenged the government's authority in Michoacan state is showing no signs of slowing.
The vigilante groups held onto their guns on Wednesday as federal authorities struggled to reign in the fast-growing citizen militias. The groups sprang up in response to heavy violence from the area's drug cartels but have morphed into heavily-armed militants.
The government initially tolerated, possibly even encouraged, the groups in their fight to challenge the drug cartels but now that the violence has grown out of control they are now calling for them to drop their arms and go home. How did the vigilante groups grow out of control in the first place? Who are they fighting?
Carrie Kahn, NPR Correspondent based in Mexico City.