Armored Vehicles Roll Into Rio de Janeiro Slum

Authorities launched a massive sweep of the Alemao favela complex in northern Rio de Janeiro, Brazil, Sunday morning.

Military police told reporters they were entering the virtually impenetrable labyrinth of slums, searching for drug gang leaders and illegal drugs.

CNN affiliate TV Record showed images of armored vehicles entering the slum Sunday morning, followed closely by police trucks and helicopters equipped with military rifles.

Police told TV Record that they had arrested at least nine people, confiscated heavy weapons and seized four tons of marijuana.

On Saturday, police spokesman Mario Sergio Duarte declared an ultimatum against drug gangs in the complex, stating that a military attack was imminent.""We will not retreat in our decision to bring peace to Rio,"" Duarte said. ""We are in our final stages of reaching the traffickers in the Alemao complex.""

Police had offered drug gang leaders the chance to surrender, but they refused, Brazilian military police Col. Lima Castro said in an interview with CNN affiliate Band News Sunday.

Castro said police were asking any residents who live in the slum to stay home and take cover to avoid being hit by any stray bullets during the takeover.

A police officer was hit in the arm by a bullet as authorities entered, police told TV Record."