In one of the incidents, a firefight in the Alemao complex of slums hugging the highway that leads to Rio's international airport began late Sunday night when officers on patrol were met with heavy gunfire, the police said in a statement.
Two gang members were injured in the exchange and rushed to a local hospital, where they later died. Two police officers and an adolescent boy sustained injuries.
Earlier on Sunday, in an apparently unrelated attack, a 30-year-old police officer in Alemao was shot in the face when he was surprised by a group of armed traffickers. He died in the hospital Monday morning.
Alemao has long been a hub for criminal activity but was occupied by police in 2010 as part of an effort to clean up and boost investment in the more than 1,000 shantytowns in Rio ahead of the World Cup and the 2016 Olympics.
Since the slum's so-called pacification, its overhead cable cars have become a major destination for foreigners looking to get away from Rio's sun-filled beaches and tourist landmarks and catch a glimpse of how the city's poorer, largely minority population lives.
Also on HuffPost