A man is detained by police officers during a police operation against drug trafficking at the favela do Penha, in Rio de Janeiro, Brazil October 28, 2025. REUTERS/Aline Massuca
A member of the tactical police unit stands on a vehicle during a police operation against drug trafficking at the favela do Penha, in Rio de Janeiro, Brazil October 28, 2025. REUTERS/Aline Massuca
Members of the military police special unit detain suspected drug dealers during a police operation against drug trafficking at the favela do Penha, in Rio de Janeiro, Brazil October 28, 2025. REUTERS/Aline Massuca
Suspected drug dealers sit on the ground after they were detained by members of the military police special unit, during a police operation against drug trafficking at the favela do Penha, in Rio de Janeiro, Brazil October 28, 2025. REUTERS/Aline Massuca TPX IMAGES OF THE DAY
A person looks on behind a burnt car during a police operation against drug trafficking at the favela do Penha, in Rio de Janeiro, Brazil October 28, 2025. REUTERS/Aline Massuca TPX IMAGES OF THE DAY

RIO DE JANEIRO (Reuters) -At least 64 people died on Tuesday in Rio de Janeiro's most deadly police operation ever, which targeted a major gang days before the city hosts global events related to the United Nations climate summit known as COP30.

Police have often conducted large-scale operations against criminal groups ahead of major events in Rio, which hosted the 2016 Olympics, the 2024 G20 summit and the BRICS summit in July.

Next week, Rio hosts the C40 global summit of mayors tackling climate change and Prince William's Earthshot Prize, which will feature celebrities including pop star Kylie Minogue and four-time Formula One world champion Sebastian Vettel.

The programming is part of the run-up to COP30, the United Nations climate summit held in the Amazon city of Belem from November 10 to November 21.

The death toll confirmed by Rio Governor Claudio Castro on Tuesday, which included four police officers, was more than twice Rio's most deadly previous police operation.

"We stand firm confronting narcoterrorism," Castro wrote on social media about the operation, which he said involved 2,500 security personnel across the Alemao and Penha favela complexes, near the city's international airport.

Rio's favelas are poor, densely populated settlements woven through the city's hilly oceanside terrain. Smoke rose early on Tuesday over the iconic skyline as gangs burnt cars to slow the advance of armored vehicles while bursts of gunfire rang out.

Police released videos showing suspects using drones armed with grenades against the police. The footage also showed armed men fleeing into a forested area near the operation.

After the most intense fighting subsided, a Reuters journalist saw police from a special operations unit rounding up dozens of shirtless men. Sobbing family members gathered outside of a public hospital attending to those injured.

The Rio state government called Tuesday's operation the largest ever targeting the Comando Vermelho gang.

Justice Minister Ricardo Lewandowski said the federal government had not received any request for support from state authorities prior to the "bloody" operation, adding he had been following developments through media reports.

The clashes disrupted the routines of dozens of schools and medical facilities, redirected bus routes and snarled traffic across several neighborhoods in the state capital.

Castro confirmed 81 arrests as authorities sought to serve 250 arrest and search warrants in an operation targeting alleged drug kingpins and their money laundering operations.

However, some civil society groups criticized the heavy casualties in a military-style operation. Carolina Ricardo, executive director at security think tank Sou da Paz, called it a tragedy.

"This is a completely failed approach, because it does not actually target the links in the drug production chain," she said.

(Reporting by Rodrigo Viga Gaier; Additional reporting by Aline Massuca in Rio de Janeiro, Andre Romani in Sao Paulo, Lisandra Paraguassu in Brasilia; Writing by Gabriel Araujo; Editing by Brad Haynes, Rod Nickel, Nia Williams, Nick Zieminski and Deepa Babington)