A small war took place last week in Rio de Janeiro, Brazil, between Brazilian forces and hundreds of drug traffickers holed up in the shantytown complex dubbed Complexo do Alemão. After recent efforts by officials to pacify Rio's drug and gang-related violence ahead of the upcoming the 2014 World Cup and the 2016 Olympics Games, drug gangs struck out last week - attacking police stations and staging mass robberies. After days of preparation, Brazilian security forces launched a raid in the Complexo do Alemão, where between 500 and 600 drug traffickers were holed up. At least 42 people were killed in the violence last week, with security forces taking control of many neighborhoods. A relatively low number of arrests were made, and authorities warn of further conflict as continue to flush out more suspects in Rio's maze of favelas. Alleged drug traffickers who did not want to identify themselves, pose for a photo as they stand on a street at a slum in western Rio de Janeiro. A police officer hands packages of marijuana seized during an operation against drug traffickers to a fellow officer at the Complexo do Alemão slum in Rio de Janeiro. Soldiers aim their weapons during an operation against drug traffickers at the Complexo do Alemão slum.