At least 64 individuals lost their lives in a police operation against the criminal organization Comando Vermelho in Rio de Janeiro's northern districts - the biggest and most lethal operation in the Brazilian state's past.
Four security agents were among those killed during the security mission in the neighborhoods of Alemão and Penha, local authorities said. In excess of 80 individuals were arrested.
Violent conflicts broke out when about 2,500 security personnel entered the area on the morning of the operation. The criminal organization countered with armed resistance, setting fire to barriers and using drone-dropped explosives, authorities confirmed.
The International human rights organization said it was "shocked" by the security action, urging "swift and comprehensive examinations".
The informal settlements close to the aerial transportation hub is regarded as the headquarters of a major criminal organizations.
Local authorities said no less than 50 of those killed were "indicated by police as suspected of being criminals".
Numerous individuals were injured, including innocent bystanders trapped in shooting.
Community members have described the mountainous region - home to about 300,000 individuals - to a "battlefield" since the operation began.
Access ways continue shut in the entire neighborhood.
The Comando Vermelho organization has been growing their control throughout the region, growing illegal substance trade paths and power in the informal settlements.
Security forces reported in excess of 200kg (441lb) of narcotics were confiscated in the operation, along with multiple guns.
The combined action by various security forces comes after a twelve-month inquiry.
Numerous alleged criminals are considered affiliates of a group from the northern region who are at the moment taking refuge in Rio de Janeiro.
Major law enforcement actions are frequent in the country before important worldwide conferences in the country.
The international environmental meeting COP30 is taking place in the city of Belem in the north in the eleventh month.