World

Police take over for army as 'pacifying force' in violent Rio de Janeiro slum

  • A military police officer, left, stand guard as a Brazilian Army soldier leaves the Nova Holanda shantytown, part of the Mare slum complex in Rio de Janeiro, Brazil, early Friday, May 1, 2015. The Brazilian Army departed from four additional areas of the Mare slum complex during the second phase of an operation to hand over control of the violent slums to Rio's military police. (AP Photo/Felipe Dana)

    A military police officer, left, stand guard as a Brazilian Army soldier leaves the Nova Holanda shantytown, part of the Mare slum complex in Rio de Janeiro, Brazil, early Friday, May 1, 2015. The Brazilian Army departed from four additional areas of the Mare slum complex during the second phase of an operation to hand over control of the violent slums to Rio's military police. (AP Photo/Felipe Dana)  (The Associated Press)

  • Brazilian army soldiers leave the Nova Holanda shantytown, part of the Mare slum complex in Rio de Janeiro, Brazil, early Friday, May 1, 2015. The Brazilian Army departed from four additional areas of the Mare slum complex during the second phase of an operation to hand over control of the violent slums to Rio's military police. (AP Photo/Felipe Dana)

    Brazilian army soldiers leave the Nova Holanda shantytown, part of the Mare slum complex in Rio de Janeiro, Brazil, early Friday, May 1, 2015. The Brazilian Army departed from four additional areas of the Mare slum complex during the second phase of an operation to hand over control of the violent slums to Rio's military police. (AP Photo/Felipe Dana)  (The Associated Press)

  • Brazilian Army soldiers leave the Nova Holanda shantytown, part of the Mare slum complex in Rio de Janeiro, Brazil, early Friday, May 1, 2015. The Brazilian Army departed from four additional areas of the Mare slum complex during the second phase of an operation to hand over control of the violent slums to Rio's military police. (AP Photo/Felipe Dana)

    Brazilian Army soldiers leave the Nova Holanda shantytown, part of the Mare slum complex in Rio de Janeiro, Brazil, early Friday, May 1, 2015. The Brazilian Army departed from four additional areas of the Mare slum complex during the second phase of an operation to hand over control of the violent slums to Rio's military police. (AP Photo/Felipe Dana)  (The Associated Press)

Rio de Janeiro's state government says police have begun replacing the soldiers stationed as a "pacifying force" in part of the sprawling Mare slum.

The transition began early Friday in four of the 16 shantytowns that make up the Mare complex, which is near Rio's international airport and sandwiched between three key expressways.

Army soldiers moved into Mare about a year ago under a pacification program meant to push out drug trafficking gangs that ruled the slums for decades.

The program is seen as key to bringing security to violent Rio before the city hosts the 2016 Olympics, but it has recently come under criticism.

Residents of some "pacified" slums have accused police of brutality, and several highly publicized cases of officers killing unarmed residents have emerged.