Rio de Janeiro (CNN) -- Soldiers in full combat gear move silently through a sprawling shantytown in northern Rio de Janeiro, pointing weapons down narrow alleys and poking through sacks of cement in search of drugs.
Residents walk by, barely looking at the troops sent in to occupy the Complexo da Mare as an emergency response to escalating violence in the city's notorious favelas.
Some 2,500 army troops and marines have moved in to reinforce police in an operation aimed at securing the slum, home to 130,000 people, ahead of the World Cup, which runs from June 12 to July 13..
Seizing control from drug gangs was deemed a priority because the shantytown lies just a few kilometers from Rio's international airport.
"It's not a peaceful operation because we have three different criminal gangs here and they are rivals," Gen. Roberto Escoto told CNN.