(Adds context about economic slowdown, protests, police fatigue)
By Paulo Prada
RIO DE JANEIRO, Jan 21 (Reuters) - Daily shootouts and recent police slayings of two alleged drug traffickers are rattling two of Rio de Janeiro's most prominent slums, communities that until recently showcased attempts to pacify historically violent shantytowns.
Just five months before Rio welcomes visitors for the soccer World Cup, and two years before it hosts the Olympics, the communities of Pavão-Pavãozinho and Cantagalo are bracing for what residents and richer neighbors fear is the return of a decades-old turf war between armed drug gangs and police.
The communities, sprawls of bare brick on hills over the prosperous beachside districts of Ipanema and Copacabana, are among the most emblematic of Rio's favelas, as the slums are known. The two favelas were hailed by authorities as triumphs in a campaign to expel criminals using a strong police presence.
Lately, though, violence in both favelas is rekindling, casting doubt on the sustainability of the so-called "pacifications." It also renews fears about security and public authority during big events that political leaders, now grappling with an economic slump, hoped would showcase a modern, transformed Brazil.
"We really thought things had gotten better here," said Alzira Amaral, president of the neighborhood association of Pavão-Pavãozinho, a dense wall of jerry-built homes that climb up a steep outcropping near the Atlantic shoreline.
"Now," she added, lamenting the return of regular gunfire, "we don't know what to think."
The pacifications were supposed to pave the way for development of long-neglected areas of Rio, Brazil's second-biggest city and a metropolitan area home to 11 million people. Local authorities, cocksure during a decade-long boom that fizzled just as the pacifications took root, promised to free the favelas from criminals and reverse decades of neglect.
CULTURE OF VIOLENCE
To date, 36 areas have been "pacified." Over 9,000 police patrol favelas home to 1.5 million. Initial success in evicting the gangs was applauded but the pacifications have also been criticized for merely displacing crime to other neighborhoods.
And recently, the crime, along with growing unease, is creeping back into pacified zones. Residents who once welcomed the cops are increasingly disappointed by what they see as a lack of crucial public investment that was supposed to follow.
Meanwhile, police face a backlash in occupied favelas because of oppression, violence and other alleged human rights abuses. Corrupt officers in Rocinha, another well-known slum, were arrested last year for the torture and disappearance of a local bricklayer they claimed had ties to drug rings.
Sensing the growing discontent, drug traffickers have ordered gangs to reconquer territory. They are also seeking to rally at a time when police and political leaders are fatigued from nearly a year of protests because of the sluggish economy, rising prices, corruption and other ills.
"The criminals believe now is the time to strike back," said Alba Zaluar, an anthropologist at the State University of Rio de Janeiro. "With tension and anger in these communities it's easier for gangs to go back and impose themselves through a tried and true culture of violence."
Pavão-Pavãozinho and Cantagalo, home to more than 10,000 residents between them, were "pacified" in 2009. Residents awoke one morning to the arrival of hundreds of armed police who set up a base in the area and have patrolled it ever since.
For three years, their presence raised hopes that the communities were indeed ripe for transformation - despite the open sewers and intermittent water and power supplies.
Last October, an armed gang confronted police on patrol in Vietnã, a restive cluster of shacks among trees near the Pavão-Pavãozinho hilltop. In a shootout, police killed one suspect and injured another, the alleged leader of the resurgent drug faction. The leader, known locally as "Pit Bull," is believed to be recovering there but police don't know for sure.
Sporadic firefights followed the October shootout until earlier this month, when gang members and police began clashing daily. In addition to gunfire, the neighborhoods now ring regularly with blasts from homemade pipe bombs and grenades.
On Friday police killed a suspect they said was a Cantagalo drug kingpin. Gang members, using a routine tactic from the bad old days, the next morning descended upon Ipanema and ordered shops to shut in tribute to their fallen comrade.
Lt. Fabio Azevedo, subcommander of the pacification unit in the two communities, said the flare-up is a function of supply and demand. With few hideouts remaining near tourist haunts, gangs are re-establishing footholds from which to sell drugs.
"They are trying to come back, but we are not going to let them," he told Reuters. (Editing by Todd Benson, Stephen Powell and Andrew Hay)