Brazilian President Luiz Inácio Lula da Silva expressed shock at the fatalities from a massive police operation targeting Rio drug gangs that left scores dead, while residents and rights advocates accused authorities of summary executions during the country's deadliest law enforcement action to date.

Justice Minister Ricardo Lewandowski said Lula was "horrified" by the death toll from the raids on October 28, AFP reported.

"The president is horrified by the number of fatal incidents and was surprised that an operation of this scale was set up without the knowledge of the federal government," Lewandowski said.

Rio de Janeiro state police reported that at least 119 people perished, comprising 115 "narcoterrorists" and four officers.

However, the state public defender's office placed the toll even higher at 132, representing the deadliest police operation in Rio's history.

The raids, involving approximately 2,500 police officers bolstered by armoured vehicles, helicopters and drones, concentrated in northern Rio's Penha Complex and Alemao Complex neighbourhoods. The operation targeted Comando Vermelho, Rio's most powerful criminal organisation.

"The elevated lethality of the operation was expected but not desired," Victor Santos, head of security for Rio state, said at a news conference.

Police and suspected gang members exchanged heavy gunfire, with authorities accusing suspects of barricading in buses and deploying explosive-laden drones to attack police.

"This is not ordinary crime, but narcoterrorism," Governor Claudio Castro wrote on X.

However, angry residents accused police of killings amounting to a massacre, while mourners gathered in streets where bodies lay lined up.

"The state came to massacre, it wasn't a [police] operation. They came directly to kill, to take lives," one woman in Penha Complex told AFP.

"There are people who have been executed, many of them shot in the back of the head, shot in the back. This cannot be considered public safety," 36-year-old resident and activist Raul Santiago told Al Jazeera.

UN Secretary-General António Guterres conveyed concern over the high death toll. "We remind authorities of their obligations under international human rights law, and urge prompt and effective investigations," Guterres's spokesman Stéphane Dujarric stated on October 29.

Castro insisted those slain were all criminals, claiming clashes largely occurred in wooded areas where civilians were unlikely to be present.

"I don't think anyone would be strolling in the forest on the day of the conflict. The only real victims were the police officers," he said.

According to Colonel Marcelo Menezes, the Special Police Operations Battalion (BOPE) formed a barrier, with officers advancing to the Serra da Misericórdia mountain range and surrounding suspects in woods where another group waited, Folha de S. Paulo reported.

Throughout the afternoon and the evening on October 28 and into the next day’s early hours, residents with motorcycle taxi driver support entered woods to retrieve bodies.

Dozens were transported to a square in Penha, where they were lined up.

Attorney Albino Pereira, representing families, identified clear signs of torture, execution and human rights violations.

"You don't even need to be an expert to see that there are burn marks [on the skin]. The shots were fired with the gun pressed against the skin. A body arrived here without a head. The head arrived inside a bag; it had been decapitated. So, this was an extermination," Pereira said.

Supreme Court Minister Flávio Dino stated the court does not impede police work but cautioned it does not legitimise illegalities.

"All these events, all these tragedies, serve to show that we need to develop a general theory of police action, especially on the political level," Dino said.

"But, at the same time, it is not about legitimising a free-for-all with bodies lying around in the middle of the woods, thrown on the ground, because that is not the rule of law."

The Rio de Janeiro Public Prosecutor's Office dispatched forensic technicians to the Institute of Forensic Medicine to conduct independent examinations.

Rights groups questioned the timing of large-scale police operations ahead of major international events. Next week, Rio hosts the C40 World Mayors Summit and Prince William's Earthshot Prize.

Later in November, Brazil welcomes world leaders for the UN climate summit COP30 in Belém, starting on November 10.

Police raids against criminal organisations remain common in Brazil's favelas, with many turning deadly, but never to the extent of the October 28 operation. In 2024 alone, approximately 700 people died during police operations in Rio, nearly two deaths every day.