Members of the militia guard the streets in Rio de Janeiro in this January photo. Militia, new, illegal security forces, are mushrooming across Rio and are made up of active and former police, private security guards and off-duty firefighters and prison guards.

Rio De Janeiro, Brazil ? For as long as anyone can remember, the cracked asphalt soccer field in the Roquete Pinto slum was off-limits to children – “reserved” by gangs selling marijuana and cocaine. Then, a few months ago, a mysterious squad of beefy men with submachine guns started patrolling on foot, and the drug dealers disappeared.

A few days ago, while gunbattles were raging in two other Rio de Janeiro neighborhoods and bystanders were shielding their children from the bullets, the barefoot teens of Roquete Pinto smiled and shouted as they kicked a ball around their freshly liberated field.

Startling transformations like Roquete Pinto’s are increasingly visible across Rio, as for-profit “militias” made up of active and former police officers, private security guards, off-duty prison guards and firefighters evict drug gangs from slums where violence used to be out of control.

Although some worry about the implications of vigilante justice, the militias have powerful sympathizers, among them Mayor Cesar Maia, who calls them “self-defense groups” and says that compared with the drug gangs, the vigilantes are the lesser evil.

The surprise is that the gangs aren’t fighting to hold their turf. In the few known cases where they did, militia gunfire turned them back.

Critics say the city risks going the way of Colombia, where violent paramilitary groups that sprang up to battle guerrillas came to hold more power than authorities in some areas.

“It’s the state that establishes law and order, not the militia,” said Sergio Cabral, governor of Rio de Janeiro state. “We won’t accept this under any conditions.”

But President Luiz Inacio Lula da Silva hasn’t spoken out against the militias, and it seems that law enforcement has fallen into a gray area in many Rio slums, and city authorities may be content to leave it at that as Brazil prepares to host Pope Benedict XVI next month and Rio stages the Pan American Games in July.

In this city of 6 million people, one of the world’s most violent, “the police provide security for the rich” and “the militias are the security of the poor,” said Marina Maggessi, a congresswoman and a former senior drug-control official. She has mixed feelings about the militias, saying they represent the “collapse of the state.”

First gaining strength in 2003 as an alternative to ineffective, often corrupt police, the illegal security forces have mushroomed since late last year and now control about 90 of Rio’s 600 “favelas,” Maggessi said. Success in slums like Roquete Pinto, meanwhile, fuels their expansion into others.

“This place was dead,” said Joao Batista dos Santos da Silva Jr., president of the Roquete Pinto residents’ association. “It was war every day.”

Like many slum community leaders, he refuses to acknowledge the existence of the militias, saying the cleanup is entirely the work of the police, even though there is no station in the slum, and not a single officer or patrol car was seen during two recent visits.

On the other hand, Roquete Pinto’s new protectors were hard to miss: Seven big men in shorts and T-shirts, silently eating lunch in a pool hall, a submachine gun and automatic pistols on the table between their plates.

In another favela, Rio das Pedras, a woman selling shampoo on the street had no doubts. “There are no muggers and no drug sellers,” said Margarida Rodrigues dos Santos, 57. “The militia won’t let them in.”