Dozens of vigilantes, who wear white T-shirts for identification, work with government forces to clear out cartel gunmen

Vigilantes who have driven a quasi-religious drug cartel from a series of towns in western Mexico entered a gang-held city on Saturday and were working with government forces to clear it of cartel gunmen, a leader of the movement has said.

Dozens of vigilante group members, who wore white T-shirts to identify themselves, were seen by an Associated Press journalist speeding into Apatzingan in the back of pickup trucks. The city of 100,000 in Michoacan state has been under effective control of the Knights Templar cartel for several years.

"Federal forces are working with self-defense groups," vigilante leader Hipolito Mora said over telephone from the centre of Apatzingan. "Guys from the self-defence groups are moving around the city, co-operating in certain ways with the federal government. Many, many people have been detained."

Mora said federal police controlled security in the city and both armed and unarmed members of the "self-defense" movement were working with them to identify Knights Templar hideouts. He said approximately 200 gang members were arrested, including the brother of one of its leaders, Enrique "Kiki" Plancarte. The government made no immediate comment.

The vigilantes' presence in the city is both a symbolic and tactical boost for the movement.

The control of the Knights Templar group was once so complete that it would have been unthinkable for any rival to enter Apatzingan. The Knights Templar often travelled in vehicles marked with its symbol, a red cross, and sponsored demonstrations calling for the federal police to leave the city.

The cartel promotes itself as a mystic Christian order dedicated to protecting the population from abuse at the hands of the military and police. It ran "training schools" including one in Apatzingan, that taught courses in leadership portraying cartel members as clean-living men of honour, steeped in Asian religion alongside Catholicism. Its members not only lived off methamphetamine and marijuana smuggling and extortion, but controlled much of the local economy.

In October, vigilantes tried to march into Apatzingan but were turned back by soldiers who said they couldn't enter with weapons. A convoy of hundreds of unarmed self-defence patrol members returned the next day and successfully entered the city, where they were met by gunfire, presumably from the Knights Templar.

In apparent retaliation to the attempted incursion, suspected cartel members mounted co-ordinated attacks on vigilante positions, killing five, according to police. They also destroyed government electrical facilities, including power distribution plants and electrical sub-stations, in 14 towns and cities around Michoacan, cutting power to hundreds of thousands of people.

Mora said on Saturday that this latest incursion was "a triumph".

The vigilantes' knowledge of the city is already boosting government operations against the Knights Templar, according to Mora, who said self-defense force members were going door-to-door pointing out suspected cartel members to federal police and helping police man checkpoints on the roads in and out of the city.

"They're all around the city watching to see if members of the Knights Templar are coming or going," he said.

Mexico legalised the growing "self-defence" movement in Michoacan late last month, saying they would be incorporated into quasi-military units called Rural Defense Corps. Vigilante groups estimate their numbers at 20,000 men under arms.

Mora said vigilantes who have been formally incorporated into the Rural Defence Corps were armed, while those not yet registered had no weapons. He said he and his close associates were unarmed, and were there primarily to attend an afternoon rally for peace and the rule of law called by an Apatzingan clergyman who has opposed the Knights Templar.

Vigilantes began rising up last February against the Knights Templar reign of terror and extortion after police and troops failed to stop the abuses. Vigilante leaders have been asked to submit a list of their members to the Defense Department and are being allowed to keep their weapons as long as they register them with the army.

The military is giving the groups "all the means necessary for communications, operations and movement," according to the agreement.