Slum dwellers descended from a hillside shantytown on this city's poor north side, burning tires and two city buses after police killed at least three people in shootouts with alleged drug gangs Tuesday.

Rio de Janeiro state police inspector Ricardo Oliveira said three alleged drug gang members were killed in the shootout in the Mangueira slum during an operation to retrieve stolen goods.

Residents, however, claimed that police killed four people in the shooting including a child, according to local news media.

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Bus burnings and rioting are common reactions to police killings in the slums that line this city's hillsides and which are largely controlled by heavily armed drug gangs.

No one was reported injured on either of the buses, Oliveira said.

The latest outbreak of violence comes days after hundreds of federal police were dispatched to Rio to battle a wave of gang violence ahead of a summit of South American leaders, next month's Carnival celebrations and the Pan American Games in July.