Complexo do Alemão, Rio de Janeiro. Photo by Ben Tavener.

Police called in reinforcements in favelas (slum areas) in the north of Rio de Janeiro earlier on Wednesday, despite the area having been previously ‘pacified’ as part of the city’s policy of ridding poorer communities of armed criminal gangs and integrating them into the wider city.

Military police have ramped up their presence in the Complexo do Alemão (see photo gallery), a sprawl of favelas in the north of the city, after unrest in the area on Tuesday, which included a protest by residents following the arrest of two young men on Monday.

Police say the pair had arrest warrants issued against them for drugs charges, but around 100 residents took to the streets to protest, defending their innocence. Police used non-lethal force – including tear gas and pepper spray – to disperse crowds, and are now investing whether there were criminal factions behind the protests.

Local media reports that, during the unrest, at least on man took out a gun and fired into the air, and a group of ‘activists’ threatened to set fire to a fuel tanker being used a barricade along with burning tyres and trash cans, further increasing the tension.

Later on Tuesday, the Nova Brasília Police Pacification Unit (UPP) – part of the Complexo do Alemão – came under attack in what appears to be a reprisal, and police battled gunmen into the favela. Investigations are ongoing to establish who the gunmen were.

On Wednesday both military and civil police forces searched vehicles in the favela complex, including those from the local UPP.

Rio’s 38th UPP

Meanwhile, in the west of Rio, police are preparing for the city’s newest UPP in Vila Kennedy – the 38th of the forty UPPs that Rio security secretary José Beltrame announced in 2011, and only the second in the west of the city.

The city has traditionally prioritised areas frequented by tourists and close to new sporting venues, but is now reaching areas located further away from the center.

Police previously announced they would occupy Vila Kennedy, planned for tomorrow (Thursday), due to the high levels of violence seen in the area: 29,372 cases were registered in 2013 alone – up over seven percent on the previous year.

Local media say the region is now calm afte criminals set to be flushed from the area shot at electricity transformers, leaving parts of the district without power. The wider area has since seen a significantly-increased police presence.

Correspondents say that although some UPPs have been successful in bringing greater security to favela communities, there is often still an overwhelming sense of distrust on both sides and armed battles have occurred sporadically.

Some 22 percent of Rio’s population, estimated to be around 7 million people, live in favela communities.

Police, which have faced running battles with armed gangs engaged in both drugs and arms trafficking, have been accused of brutality against local residents – and the notorious case of favela resident Amarildo Dias da Souza, who disappeared from the city’s largest favela, Rocinha, in July 2013, remains fresh in the minds of Rio’s poorer communities.

Investigators say, along with drugs gangs in the area, the main suspects in the bricklayer’s disappearance – and suspected torture and murder – remain police officers from the local UPP.

Extended version of article written for Anadolu Agency