Hundreds of gang members have been filmed fleeing from a Rio shantytown after police invaded the slum.
Elite police units in borrowed navy tanks rumbled through a heavily fortified favela in the Brazilian city in an effort to apprehend drug gang leaders blamed for five days of widespread violence, as scores of armed youths fled to a neighbouring area.
Authorities said the gangs had erected roadblocks on major highways to rob motorists en masse, torched more than 40 cars and buses, and fired at police outposts - all to protest against a security programme that has been pushing them from the favelas where they've held sway for decades.
The officers arrived in the Vila Cruzeiro shantytown under the cover of police helicopters and amid the rattle of high-calibre gunfire despite the gang members' efforts to block access with burning vehicles.
As police entered, alleged gang members were seen fleeing down jungle-covered hills, across an area known as "the green hell," to a neighbouring gang stronghold, Alemao.
At least 30 people have died, many believed to be suspected drug gang members, and more than 150 suspects arrested in police raids at nearly 30 shantytowns in the northern and western parts of Rio.
Authorities also have established 13 permanent police posts in the favelas as part of their efforts to clean up the seaside city before it hosts the World Cup football final in 2014 and the 2016 Olympics.
Police have not released the identities of all those killed, but spokesman Henrique de Lima Castro Saraiva did acknowledge on Wednesday that "bystanders would be affected" by the battles.