Police used helicopters and armored cars in an attempted raid on a crime-ridden shantytown on Wednesday, that led to four dead traffickers and six other people injured.
About 1,200 officers, aided by helicopters and armored cars were deployed around the sprawling Alemao shantytown complex, where an ongoing war between drug traffickers has claimed 31 lives since May and left some 81 people injured.
Residents were forced to scramble for cover and schools and stores closed as as the operation began early Wednesday, said Police spokeswoman Lucia Guerra.
After securing low-lying areas, police attempted to enter several of the narrow alleys that line the hillside shantytowns and were met by automatic weapon fire and hand grenades.
Police used a backhoe to remove a truck that drug gangs placed in front of the entrance to the Grota shantytown where the four alleged gang members were killed in heavy fighting, Guerra said.
The injured included a police officer, two women in their twenties and a 13-year-old girl, Guerra said.
"It's kind of complicated, it's tough. We have six people shot here at the hospital from all over the Alemao complex," said Luiz Claudio dos Santos, a community leader.
Shootout between drug gangs and police are daily occurrence in this city with annual homicide rate of around 50 per 100,000 residents.
But concerns over the violence have grown as the city of 8 million prepares to welcome thousands of athletes for the Olympic-style Pan American Games in July.
Russian officials have repeatedly declared that Israeli aviation poses a threat to the Russian military in Syria.