The United Nations human rights office called on Friday for an independent investigation into a Brazilian police operation in a Rio favela against drug traffickers, which left 25 dead including a police officer.
Thursday's operation with helicopters appeared to be the deadliest in a decade, in a long-standing history of "disproportionate and unnecessary" use of force by police, UN human rights spokesman Rupert Colville told a U.N. briefing in Geneva.
"We call for the prosecutor to conduct an independent and thorough investigation into the case according to international standards," Colville said.
Force should only be used as a last resort and police did not take steps to preserve evidence at the crime scene, he said.