At least 18 people were left dead after a police raid on a complex of favelas in Rio de Janeiro.
Officers raided the Alemao complex to target a criminal group that had stolen cars, robbed banks and invaded nearby neighbourhoods.
Videos circulating on social media showed intense shootouts between criminals as well as a police helicopter flying low over the small, brick houses.
At least 18 people died in the raid including one police officer, 16 alleged criminals and a female bystander, police said.
The operation involved around 400 officers, four aircraft and 10 armoured vehicles.
The lopsided death toll ignited fears of human rights abuses.
"There are signs of major human rights violations, and the possibility of this being one of the operations with the highest number of deaths in Rio de Janeiro," the state public defender’s office said in a statement.
Ronaldo Oliveira, an investigator with Rio’s police force, said officials would have rather just made arrests of suspects “but unfortunately they chose to fire at our policemen.”
Rio state Governor Cláudio Castro, who is running for reelection in October, said on Twitter he lamented the police officer’s death.
“I will continue to fight crime with all my strength. We will not back down from the mission of guaranteeing peace and security to the people of our state,” Castro said.
In another tweet, Castro said his main rival in the elections, leftist Marcelo Freixo, defends criminals who attack police, “such an important institution that makes us so proud.” Freixo responded that the governor “uses police to make politics.”
The government’s strategy for tackling violence and organised crime, an approach that regularly sees deadly police operations, has come under criticism. A raid in Rio’s Vila Cruzeiro favela in May killed more than 20 people.
Alemao is a complex of 13 favelas in northern Rio, home to about 70,000 people. Nearly three-quarters of them at Black or biracial, according to a July 2020 study published by the Brazilian Institute of Social and Economical Analyses.