Nine people were killed Wednesday in a police operation targeting criminal gangs in Rio de Janeiro, authorities said, the latest in a week of security force raids that have left at least 44 dead across Brazil.

The Rio raid came after days of deadly police crackdowns on drug trafficking gangs that have left 16 dead in Sao Paulo state and 19 killed in the northeastern state of Bahia.

Rio state police said officers had returned fire after coming under attack during a raid on a meeting of organized crime bosses in the Complexo da Penha group of favelas, on the city's north side.

Authorities face mounting calls for independent investigations of alleged police abuses in Brazil, where the security forces have been accused of human-rights violations in their war with heavily armed drug gangs.

Police said the Rio operation came after officers received intelligence on a high-level meeting by gang leaders.

"A clash occurred when police teams came under attack by gunmen at the scene," state police said in a statement.

"Eleven suspects were wounded" and taken to the hospital, it said. "Nine of them died of their injuries."

Two policemen were also wounded and are in stable condition, it added.

Residents described the favela complex as a scene from a war zone during the raid, with locals left cowering inside their homes -- mostly small shacks packed tightly on the hillsides.

"Businesses are all closed. People can't leave home to take their kids to school. You just have to take cover in a safe place and wait for the shooting to end," one resident told TV Globo, speaking on condition of anonymity.

AFP reporters outside the hospital where the wounded were taken described anxious residents waiting for news on injured relatives, flanked by a heavy police contingent as helicopters hovered overhead.

Police said makeshift barricades had been set up across the neighborhood to slow officers' advance.

They also said they had seized seven assault rifles, grenades and ammunition in the operation.

The dead included two gang leaders, police said.

They did not report any arrests.

Rio state legislator Dani Monteiro noted the operation came just over a year after a May 2022 raid in the same favela complex that left 25 dead, the second-deadliest police operation in the city's history.

Calling that raid a "massacre," she criticized Rio state Governor Claudio Castro, a security hardliner and ally of far-right former president Jair Bolsonaro.

"Castro's (in)security policy must stop!" Monteiro, a lawmaker for the left-wing PSOL party, wrote on X, formerly called Twitter.

- Alleged abuses -

In Sao Paulo, state police launched a massive anti-gang operation Friday, a day after a 30-year-old special forces officer was shot dead while on patrol in the port city of Guaruja.

Authorities said Wednesday that 16 alleged criminals have been killed so far in the ongoing operation there, updating an earlier toll of 14.

In the northeastern state of Bahia, officials meanwhile said 19 suspects in three different cities had been killed since Friday in clashes with police.

In all the cases, authorities said police had returned fire after coming under attack.

However, the killings have drawn criticism from rights groups in Brazil, where accusations of abuses by security forces are frequent.

The Sao Paulo operation shows "clear signs of seeking vengeance for the death of a police officer," said Amnesty International.

"Residents have accused officers of abuses, intimidation and torture."

The rights group sharply criticized Sao Paulo Governor Tarcisio de Freitas, another Bolsonaro ally, for "legitimizing police violence."

Leftist President Luiz Inacio Lula da Silva's justice minister, Flavio Dino, has also criticized the operation, saying the police reaction "doesn't seem proportional to the crime committed."

Protests against police violence have been called for Wednesday in Guaruja and Thursday in Sao Paulo outside the state public security ministry.

Last year, 6,429 people were killed by police in Brazil, a country of 200 million people, according to the watchdog group Public Security Forum.