Shootouts between Rio's police and drug gangs in favelas in the so-called Complexo do Alemao killed three people and injured another five on Tuesday.
A policeman was shot in the head and died immediately in the favelas Vila Cruzeiro and Grota, which are situated in the city's north zone.
A team from the elite Special Operations Police Squad (BOPE) was sent to the region to rescue other officers trapped in the shootouts with the drug dealers.
The BOPE took four armored vehicles, but one of them had to be towed out of the conflict area because a bullet had damaged its engine.
The atmosphere in the neighborhood is still regarded as "tense," as the drug gangs have seized public buses and used them to block the streets that lead to the favelas in an attempt to prevent the police from getting in.
As a result of the conflict, schools had to cancel their afternoon classes, forcing around 4,000 students to stay at home Tuesday.
In June, confrontations between the police and gangs killed 19 people in the Complexo do Alemao, nine of whom were said not to be involved in the trafficking of drugs.