Fifty federal police officers armed with black assault rifles guard the gates of an exclusive private hospital in this cosmopolitan capital.

They are patrolling the polished stone lobby, standing sentry under palm trees, surveilling the Starbucks. Private security guards and local police man the doors, driveways and elevators.

“We are all here for him,” one federal police officer said.

That would be for José Manuel Mireles, a wiry, mustachioed surgeon who once worked for the Red Cross in California and who is now Mexico’s most famous militia leader. Mireles arrived at the hospital this week as a patient, after his small airplane crashed in his home state of Michoacan, where he is leading a growing civilian rebellion against the drug cartel known as the Knights Templar.

The massive security presence at the Medica Sur hospital speaks to both the newfound fame and the national importance of Mireles, but also to the tricky position in which Mexico’s government finds itself with regard to the rebel movement. Since the spring, when Mireles banded together with local residents, officials in President Enrique Peña Nieto’s government have described the citizen fighters as operating outside the law. But in recent months, as more towns have joined in, Mireles’s stature has only grown.

“Yes, we are protecting him,” Interior Minister Miguel Ángel Osorio Chong said this week. “Because he is a person who has wounded the cartels, particularly the Templars.”

Osorio Chong told reporters there was no sign of foul play when Mireles’s airplane went down Saturday as he was traveling from Guadalajara to his home town of Tepalcatepec. One of the five passengers onboard was killed, and 55-year-old Mireles suffered head injuries and a dislocated jaw. Osorio Chong blamed the crash on pilot error, and other senior officials said there are no plans to arrest Mireles.

If Mireles returns to lead his movement, which has spread to about 20 towns in Michoacan, his survival will undoubtedly burnish his growing legend. The doctor, who used to live in Sacramento and often carries a hand-held radio in his white hospital jacket, has said he rallied villagers against the Knights Templar to stop rampant extortion by cartel members as well as a wave of abductions and rapes of women and girls. Peña Nieto dispatched thousands of soldiers to Michoacan last year, but residents say the citizen militias have had far more success.

“We do the work of the government, and we are willing to die fighting,” Mireles has said.

In Internet videos, a leader of the Knights Templar, Servando Gómez Martínez, a.k.a. “La Tuta,” has accused the civilian militias of being proxy fighters for a rival drug gang, New Generation, which operates across the state line in Jalisco.

Managing the volatile and confusing mix of gunmen in Michoacan has become one of the most vexing problems for Mexico’s government. Because Mireles and his vigilantes consider local officials inextricably linked to the drug mafias, siding with the militiamen puts the federal government at odds with its own local administrations.

Over the weekend, militiamen seized a government building in the town of Paracuaro and refused to release 11 local policemen they took prisoner. That prompted roadblocks by masked people denouncing the militia takeover — protesters who the militiamen said were working at the behest of the cartels. Para­cuaro’s mayor called for the federal government to release the police.

Elsewhere in Michoacan, local policemen have been arrested on charges of collaborating in the killings of dozens of people whose bodies were found in a mass grave in the town of La Barca in November.

Authorities have kept Mireles and his relatives out of the public spotlight while he recovers. But the heavy police presence worries some hospital officials, who fear that it could prove disruptive.

“I’ve never seen anything like this before,” said one hospital clerk as the federal police officers patrolled the lobby.