RIO DE JANEIRO — More than 3,000 police and soldiers backed by armored personnel carriers raced into Brazil's biggest slum before dawn Sunday, quickly gaining control of a shantytown ruled for decades by a heavily armed drug gang.
It was the most ambitious operation yet in an effort to increase security before Rio hosts the final matches of the 2014 World Cup and the 2016 Olympics. Officials are counting on those events to signal Brazil's arrival as a global economic, political and cultural power.
"We're taking back this territory for the 100,000 citizens of Rocinha, people who have needed peace," said Sergio Cabral, governor of Rio de Janeiro state.
The action in Rocinha is part of a campaign to drive the drug gangs out of the city's slums, where the traffickers often rule unchallenged. The city of Rio de Janeiro has more than 1,000 shantytowns where about one-third of its 6 million people live.
Authorities said it took just 90 minutes to seize control of Rocinha. Police simultaneously overran the neighboring Vidigal slum, also previously dominated by the drug gang Friends of Friends.
Both slums sit between two of Rio's richest neighborhoods, and Rocinha's ramshackle shacks climb a mountainside covered in Atlantic rain forest. Police methodically cleared alleys and streets on their way up steep, winding roads.
Huey helicopters continued to pound the air above, crisscrossing the hill and flying low over the jungle surrounding the slum, as police hunted down suspects who may have fled into the forest. By midday, local outlets reported just one arrest, though that couldn't be independently confirmed.
Residents peeked out their windows and stared as the massive armored carriers blasted up streets. Rifle-toting officers from the BOPE police units, made famous by two "Elite Squad" films, trained their weapons down narrow corridors.
Down a side alleyway, police discovered a house they said belonged to the No. 2 gang leader, Sandro Luiz de Paula Amorim, known as "Peixe," who was captured by police a few days earlier as they circled Rocinha with roadblocks.
In stark contrast to the impoverished shacks around it, Amorim's three-story home was outfitted with a large whirlpool bath, swimming pool, massive aquarium, high definition TV and just one book: the ancient Chinese military text "Art of War."
One resident applauded the police invasion. "Tell the world we're not all drug traffickers! We're working people and now they're coming to liberate us," a man yelled as police rolled by.
Marisa Costa da Silva, 54, who runs a small candy shop at the base of the slum, was less sure. "Lord knows if there will be war or peace, or even if things will be better if police take this slum," she said. "We've heard they've been abusive to slum residents in other places they've taken. I have no idea what to expect."
Rocinha's location has made it one of the most lucrative and largest drug distribution points in the city.
"Rocinha is one of the most strategically important points for police to control in Rio de Janeiro," said Paulo Storani, a security consultant and former captain in the elite BOPE police unit leading the invasion. "The pacification of Rocinha means that authorities have closed a security loop around the areas that will host most of the Olympic and World Cup activities."
Some estimates say the Friends of Friends gang brings in more than $50 million in drug sales annually in Rocinha and Vidigal alone. Much of the drugs are sold to tourists staying in the posh beach neighborhoods of Leblon, Ipanema and Copacabana and to middle- and upper-class Brazilians who live there.
"This action is a huge blow to the structure of drug trafficking in Rio de Janeiro and against the second-largest drug faction," Storani said. "Beyond that, it's essential to have security in this area simply because of the huge number of people who circulate there."
Law enforcement agents will remain in Rocinha for an undetermined time, said Alberto Pinheiro Neto, head of operations for the military police.
Officials are now calling on the shantytown's residents to help law enforcement find drugs and weapons hidden in the community. The head of Rio's civil police, Marta Rocha, made a special appeal to the "mothers, sisters, grandmothers, aunts" to collaborate with the peacekeeping effort.
"Women of Rocinha, give us this information, bring us the news that will allow us to sweep through this territory that belongs to the people of Rocinha," she said. "The day is starting. There is no going back. I am sure the population will help."
The invasion of Rocinha comes near the end of a watershed year in the fight against drug gangs. Rio's program of installing permanent "police pacification units" in slums started in 2008.
The slums initially targeted were not among the most violent. But last November, gangs struck back with a weeklong spree of attacks, burning buses, robbing motorists on highways and spreading fear and chaos. At least 36 people died in the violence, mostly suspected drug traffickers fighting with police.
The surge of violence prodded police to invade the much-feared Alemao complex of slums on Rio's north side, near a highway leading to the international airport. Police routed the gangsters and took control within hours, imbuing the city with a new confidence that its security woes might be overcome even though most gang leaders had escaped capture.
A year later, the operation in Rocinha comes after careful planning and at a time chosen by authorities.
Police officials openly announced when they planned to invade Rocinha. They've used that tactic before and say it's led to fewer firefights during the incursions, with gang members either fleeing or simply laying down their weapons before police arrive. Up to 2,000 officers are expected to be involved.
In recent days, police set up roadblocks at Rocinha's entrances to capture the slum's fleeing drug kingpins.
The effort paid off Thursday, when police captured Antonio Bonfim Lopes, known as "Nem," who was the most-wanted drug trafficker in Rio. He was found hiding in the trunk of a car. His top lieutenants were also captured in recent days.
• Associated Press writer Juliana Barbassa contributed to this report.