At least 25 people including a police officer have been killed in a shootout in Rio de Janeiro, according to local media.
The shootout took place during a police operation in a favela in the Jacarezinho area of the city, reports the BBC.
Civil Police launched the operation after receiving reports that drug traffickers were recruiting children for their gang.
Two passengers on a metro train were hit by bullets but survived.
Civil Police in the city confirmed the death of one of their officers, police inspector Andre Leonardo de Mello Frias. A statement on Facebook said "he honoured the profession he loved and will be missed".
According to local news, the gang targeted in this raid engages in drug trafficking, mugging, murders and kidnappings.
Rio de Janeiro is one of Brazil's most violent states and vast areas are under the control of criminals, many of them linked to powerful drug-trafficking gangs.
Security forces in Brazil have often been accused of excessive use of force against the civilian population during anti-crime operations in major cities.
A court ruling last June had restricted police action in poor neighbourhoods of Rio during the pandemic unless it was deemed essential.
Sociology professor Ignacio Cano from the Laboratory for the Analysis of Violence at Rio State University dismissed the reasons the police gave for the raid: "To say that drug traffickers recruit children and teenagers to deal drugs is almost laughable because everyone knows that these gangs have minors who work for them.
"To say that you're going to launch a massive raid because you've discovered that traffickers recruit children is a joke."