One of Mexico's main vigilante leaders has been arrested for carrying unauthorised weapons, officials say.
Jose Manuel Mireles was held in the western state of Michoacan.
He had been a prominent leader of one of the "self-defence groups" battling drugs cartels in the state.
But in recent weeks Mr Mireles had refused to ally his group with a new rural police force. The government has urged vigilante groups to either join the force or disarm.
Mr Mireles was detained under Mexico's firearms and explosives act for allegedly carrying weapons for sole use by the military. Dozens of other suspects were also held.
The move comes after Mr Mireles survived a light aircraft crash and disappeared from view for several weeks.
On his return to Michoacan, he had refused to align his vigilantes with the government's so-called "rural defence forces".
This is an obsolete umbrella term the administration of President Pena Nieto resurrected to lend the vigilantes a degree of official legitimacy, the BBC's Mexico correspondent Will Grant reports.
Mr Mireles had often appeared in the national and international media to explain why local communities in Michoacan had risen up against the drug cartels, our correspondent says.
But Mr Mireles always viewed the central government with suspicion and openly criticised the creation of such government-approved militias. He chose instead to continue to operate outside the law.
Now, with the most recognisable leader of Mexico's self-defence movement under arrest - along with several of his closest allies - the entire future of his organisation has been thrown into question, our correspondent adds.
The vigilante groups first emerged in early 2013 as response to the violence perpetrated by the Knights Templar drug cartel, which ranges from extortion to kidnappings.
Local citizens said that they had no choice but to arm themselves as federal troops failed to guarantee their security.
The Knights Templar, which controls much of the methamphetamine trade to the US, says the vigilantes have sided with their rivals of the New Generation cartel, something the "self-defence groups" fiercely deny.