Rio de Janeiro authorities said on Friday they had identified most of those killed in the deadliest police operation in Brazil’s history, as protests were called to denounce the high number of casualties.

The operation targeting the Comando Vermelho gang that controls the drug trade in several favelas — poor, densely populated neighborhoods woven through the city’s hilly terrain — killed 121 people on Tuesday, including four police officers.

Felipe Curi, secretary of Rio’s civil police, told reporters that by Friday morning, 99 bodies had been identified. Of those, 42 had outstanding arrest warrants and 78 had prior criminal records, he said.

State officials have been describing the operation as a success, with Governor Claudio Castro saying the “only real victims” were the slain officers as he claimed that all the others killed were criminals.

The high death toll has drawn criticism from United Nations officials and security specialists. “These acts may amount to unlawful killings and must all be investigated promptly, independently, and thoroughly,” UN experts said today.

Some locals said they had found corpses with bound limbs and signs of torture, stirring protests and political backlash.

Social movements, including major labor unions, human rights groups and left-wing parties, called for a demonstration on Friday afternoon near the Penha favela complex where the raid took place.

Protesters are demanding an end to “military incursions” into favelas and accountability for the victims, according to a joint statement. They also call for the ousting of Governor Castro.

Despite mounting criticism, local security officials continued to defend the operation.

“We acted in the most transparent way possible. It was a legitimate action by the state after a year of investigations,” Curi said.

“We have nothing to hide.”