Some 500 soldiers, some in armored vehicles, swept into Rio de Janeiro's Rocinha favela Tuesday to support a police raid after gun fights broke out between rival drug gangs.

Officials said the operation was focused on the outskirts of Rocinha, especially in the forested area that borders the upscale Gavea neighborhood, where authorities say some of the drug traffickers are hiding.

Rio police, supported by the Brazilian military, "searched the jungle area of the Rocinha community," the state security office wrote on Twitter.

When soldiers are deployed in anti-crime operations in the favelas, they usually surround the area, deploy at strategic locations, and then let civil and military police conduct searches.

But "this is not a surround operation like the others," military spokesman Colonel Roberto Itamar told Globo TV news.

The military is offering "technical support" for an operation "to find hidden material that was already detected" by intelligence agents, Itamar said.

"We're searching for weapons, ammunition, explosives, all that material that's being used" by the rival gangs struggling to control the favela.

Itamar said that this was a "targeted" operation, and that the soldiers will leave Rocinha once the job is done.

Rocinha, a teeming cluster of small homes on hillsides overlooking wealthy western Rio, is Brazil's most populous favela.

Nowhere else in Brazil do rich and poor live so close together as in Rio, whose poorest neighborhoods are part of the fabric of the city and not kept at arm's length in the outskirts, as in Brasilia or Sao Paolo.

Violence is common in favelas, where around a quarter of Rio's population of 6.5 million live. Drug gangs control much of the territory and police are forced to remain on permanent alert.

The Rocinha criminal power struggle reportedly pits supporters of Antonio Francisco "Nem" Bonfim, who used to control crime in Rocinha but has been in prison since 2011, and his wayward successor, Rogerio Avelino da Silva.

- School's out -

Some 3,000 students at nine Rocinha schools were told to stay home Tuesday due to the violence. Stray bullets from gun battles can hit random civilians, and are known to land far from the fighting.

Security in Rio has declined steadily since last year's Olympic Games, to the point that the federal government two months ago sent 8,500 soldiers to help maintain security.

Tuesday's operation comes after 950 troops were sent to Rocinha in September to back police after heavily armed drug traffickers rampaged through the favela.

The troops left the favela on September 29, when officials declared the situation "stabilized."

On Friday, about 1,000 Brazilian police and soldiers launched a large-scale operation to hunt for drug traffickers in northern Rio's Morro dos Macacos favela.

Source: AFP