The Brazilian army has withdrawn from Rio's most notorious shantytowns, ending a 10-day operation that used tanks and helicopters in a failed effort to recover weapons stolen from a barracks.
Some 1,600 troops occupied 10 shantytowns, searching for 10 assault rifles and a pistol, stolen last week by gunmen wearing army-issue camouflage gear and ninja masks.
In the downtown Providencia shantytown where drug gangs battled the soldiers during the occupation, residents cheered as the 300 troops occupying the hillside slum began to leave. The drug gangs set off fireworks to celebrate the withdrawal.
The troops left because their authorisation to search for the weapons had expired, an army statement said. None of the weapons was recovered.
State Security Secretary Marcelo Itagiba said the withdrawal only ended the first phase of the operation to strangle drug-dealing operations by confiscating their weapons. He said the army would now concentrate on precise searches using police information.
The operation began with soldiers and police agents - backed by helicopters, armored carriers and tanks - swooping down on the shantytowns.
Drug gangs fired back and lobbed grenades in the Providencia Hill slum, which overlooks the parade grounds of Rio's world-famous Carnival parade.
A 16-year-old boy was killed by a stray bullet March 6, in a shootout and four bystanders were wounded on Friday.
Prosecutors called the operation unconstitutional and unsuccessfully sought an injunction to end it.
An online survey conducted by the O Globo news agency showed that 89 percent of readers supported the army's continued occupation of the shantytowns.
Rio is one of the world's most violent cities, with an annual murder rate of nearly 50 per 100,000 people. Most of the violence is confined to the city's shantytowns, often controlled by the drug gangs, and poor outskirts.
AP