rio de janeiro hundreds brazilian soldier pour rio de janeiro rocinha slum friday bid help cash-strapped state government quell drug-related violence authorities blame least four deaths several injuries week army deploy 950 troop sprawl favela respond request rio state government defense minister raul jungmann tell local television past week 60 criminals believe launch effort dominate drug trade area far city expensive real estate shoot report friday morning accord local media violence rocinha one sign backslide since launch pacification program 2008 reduce violence push drug gang set permanent outposts city 1,000 favelas police struggle maintain security gain favelas run-up 2016 olympics rio continue lose grind fiscal crisis city state lead cutbacks spend police essential service military operation rocinha friday disrupt transportation businesses area school close par back operations go work suddenly police close tunnel rocinha start patrol gun panic mouth tunnel saw people run hear gunfire one witness tell reuters request anonymity still shake outbreak violence happen midst rock rio music festival far south end city draw thousands people musical act include fergie aerosmith broadcaster globonews friday show relatively calm scenes matte green military truck file roads favela include soldier rid truck motorcycle hold assault rifle 10,000 troop rio de janeiro could mobilize need defense ministry say go back rocinha governor rio state luiz fernando pezao tell journalists brazil army deploy rio slum drug-related violence worsen