Among the dead were four Brazilian police officers, security officials told CNN.

Rio de Janeiro State Governor Cláudio Castro’s office confirmed on X (formerly Twitter) that 42 rifles were seized during the coordinated crackdown.

“So far, 81 criminals have been arrested and 42 rifles seized in the integrated operation by security forces in Alemão and Penha,” the governor’s office said in a post on X.

The city’s Civil Police said four officers were killed during the operation, which took place in Rio’s North Zone.

“The Civil Police of the State of Rio de Janeiro deeply regrets the loss of our heroes who gave their lives in defense of society during Operation Containment,” the department said in a statement posted on X.

The UN Human Rights Office expressed shock over the scale of the violence, saying it was “horrified” by the deadly police actions in Rio’s favelas.

“We are horrified by the ongoing police operation in favelas in Rio de Janeiro, reportedly already resulting in deaths of over 60 people, including four police officers,” it said on X.

“This deadly operation furthers the trend of extreme lethal consequences of police actions in Brazil’s marginalized communities. We remind authorities of their obligations under international human rights law and urge prompt and effective investigations,” the UN body added.

César Muñoz, Brazil director at Human Rights Watch, called Tuesday’s events a “disaster.”

“Disastrous police raids in low-income neighborhoods in Rio de Janeiro resulted in the killing of more than 60 residents and police. Prosecutors should lead thorough investigations into the deaths and the decisions by Rio authorities that led to this tragedy,” Muñoz said.