RIO DE JANEIRO - In a craggy back alley of the Providencia favela in central Rio, two dozen children and teenagers chat noisily while waiting for a military police van to take them for their first visit to the Olympic park.
Children attending a Jiu Jitsu course by the Pacification Police Unit (UPP) in the Morro da Providencia, downtown Rio, walk upon arrival to attend the Rio 2016 Olympic Games, in Brazil, on August 12, 2016
"Behave during the trip!" says Christian Ribeiro, one of the police officers accompanying the young residents to see a basketball game there.
The 36-year-old, who has served in the military police since 1998, also teaches jiu-jitsu, training the youths as part of a Pacifying Police Unit (UPP) social program.
The neighborhood UPPs have been deployed since 2008 to "pacify" the city's main shantytowns controlled by drug traffickers ahead of the 2014 soccer World Cup and this year's Olympic Games.
Some 38 UPP units operate across 264 favelas, home to more than 1.5 million people.
Still, drug traffickers have recently made new inroads into some favelas without social services, triggering armed clashes with police.
"I've been giving them jiu-jitsu lessons since 2010," Ribeiro says of the youths. "It's hugely satisfying to see them progress from age 10 to 16 (without falling into drug use)."
"When they first come, they are very aggressive," he adds. "We transmit the values of sport, ethics to them."
One of the unit's students became world champion in the United States last year.
- More technique than strength -
The police officers have ditched their uniforms and weapons for the trip, opting for jeans and t-shirts instead.
The visit to the Olympic park is part of the military police's 142 free community programs, which benefit more than 6,000 children, with 112 police involved.
The 40-kilometer (25-mile) journey takes place on roads reserved for Olympic participants, staff and accredited vehicles.
Just 10 minutes in, a tire on the first van explodes, forcing it to stop at the closest UPP station. After repairs, the convoy takes off again, sirens lit to speed down the corridor while the children sing at the top of their voices.
Suelen do Desterro, 19, has a purple jiu-jitsu belt. She took up the sport at the age of 14.
"Now I give lessons to the youngest kids," she says proudly. "City hall pays me. I've learned discipline, how to respect a schedule, honor commitments."
"It's a sport that requires more technique than sheer strength," she adds.
Patrick Sanches, 13, says that "for me, it changed everything."
"My behavior changed," he says. "I feel more secure and I am better behaved and polite as well. My parents now want me to do judo. They think I can compete at the next Olympic Games."
- 'Dream come true' -
"We're here!" a child yells as the Olympic rings appear in front of the park.
Several minutes later, the group enters the gates and passes through metal detectors, arriving at Carioca Arena 1 to watch Australia play China.
A group of children from the City of God favela, made famous by Fernando Meirelles's eponymous 2002 film, pass through another gate nearby. Surrounded by police officers, they proudly chant "UPP, UPP!"
Finally, they enter the park and its sporting venues.
"That's for the rich!" exclaims Juliana Medina, marveling at the sprawling, top-rate installations. "It's a dream come true," the 12-year-old adds, taking her seat.
Rio state Public Security Secretary Jose Mariano Beltrame, also sitting on the bleachers, says the authorities are distributing 2,500 tickets for children to attend the Games.
"It's a project that involves two groups -- police officers and favela dwellers -- who previously could not live together," he tells AFP.
"But there's still a lot to be done."