Updated

Police searched homes and secured the perimeter of a Rio de Janeiro shantytown Friday that has long been a stronghold for drug gangs and a symbol of their ability to rule vast areas of the seaside city with impunity.

About 80 federal police officers joined state police in door-to-door searches in the Vila Cruzeiro slum as 800 military troops, trained in surrounding and isolating conflict areas, stood ready in their headquarters, 12 miles (20 kilometers) away, to back them up.

The area had been taken by law enforcement just hours before during a five-hour operation using armored vehicles and assault rifles.

After bulletproof vehicles had their tires blown out by gangs or were stymied by burning tires, police relied on armored personnel carriers equipped with caterpillar treads to roll over or push aside barriers and enter the fortified shantytown.

Officials trumpeted their victory Friday, hailing it as a sign of a new Rio.

"If I am here telling you this area will be pacified, it's a sign things have changed," Roberto Sa, deputy public-safety secretary for Rio state, told a news conference.

"But we don't get resources by snapping our fingers. We can't do magic. The challenge is still significant, but we have a goal, and we're not giving back a single millimeter."

Slum residents, streaming out down steep, narrow alleys to jobs in the city below, had mixed reactions as officers approached them. Some ran away, and others stayed to welcome them and cooperate by showing their identification.

Marcilio Alves, treasurer of the residents association of Chatuba, one of the slums in the nearby Alemao complex of shantytowns, and whose son and ex-wife live in Vila Cruzeiro, said people were trying get back to their routines Friday.

But the community remained without electricity, as utility workers were afraid of going up the hillside to repair wiring damaged during the incursion. Residents were also nervous, because the police force's hold on the area was still seen as tenuous, and they were afraid that cooperating with law enforcement officials or talking to the news media would brand them as snitches if the gangs returned, Alves said.

"The police are saying they're going to bring order to the place, but who knows what will really happen," he said. "The traffickers, they're like a fever in a city that's sick: They go away but they come back."

More than 80 abandoned motorcycles and at least one body were found during the search Friday morning, reminders of the gang's quick retreat the day before to the Alemao complex — among the best-defended gang turf in the city.

About 192 people have been arrested or detained since the start of the widespread violence Sunday, said police spokesman Henrique de Lima Castro Saraiva. More than 96 buses and cars have been burned on major roadways, many motorists have been robbed and police outposts have been shot in the city that will host the final match of the 2014 World Cup as well as the 2016 Olympics.

It is unclear how many people died in Thursday's violence, but police said at least 25 have been killed since Sunday. Three police officers have been injured so far.

The military support was authorized late Thursday by President Luiz Inacio Lula da Silva to help police keep their hold on the occupied area and prevent gang members from escaping.

"Anything we can do for Rio, we'll do," Silva told reporters from Guyana, where he is attending a summit of the Union of South American Nations. "It is not acceptable that 99 percent of well-meaning, hardworking people who want to live in peace are affected by violent groups."

Military spokesman Enio Zanan said the military troops designated to help are trained in suppressing conflict and have served in Haiti. Two other battalions of 800 troops each could be deployed as needed over the next few days, he said.

Security officials declined to say if they would enter Alemao on Friday or if they would wait, invading the area sometime within the next six months, as had been planned earlier.

Brazil is trying to clean up the seaside city before the World Cup and Olympics. Over the past two years, authorities have established permanent police posts in 13 slums as part of an effort to bring basic services to the communities and rid them of violence related to drug trafficking.

"We took from these people what has never before been taken — their territory, their safe harbor," Rio state Public Safety Director Jose Beltrame said. "It's important to arrest them, but it's more important to take their territory."

The city's Olympic committee has complete confidence in the pacification project being carried out, and in its long-term results, the president of the Rio 2016 committee, Carlos Arthur Nuzman, said in a statement.

"The support of civil society and the population of Rio de Janeiro at this time represents the clearest demonstration that the public-safety policy pursued by the government of Rio de Janeiro is on the right track," Nuzman said.

The marines driving the armored personnel carriers for the police for the most part did not engage in the fighting, security officials said. There no reports of the vehicles' heavy weapons being used in the slum.

Police had not released the identities of all those killed in five days of clashes, but spokesman Lima Castro acknowledged Wednesday that some "bystanders would be affected" by the battles.

The oldest patient admitted to Getulio Vargas hospital during the conflict was an 81-year-old who was grazed by a bullet, and the youngest, a 10-year-old child hit with grenade shrapnel, said Rio Health Department spokeswoman Valeria Bravo.