The authorities in Rio say they will send more soldiers onto the streets to bolster security in the city during the Olympic Games.
The move comes after a police officer was shot in the head on Wednesday after he and two others working on security at the Olympics got lost near a favela and encountered gunfire.
Justice Minister Alexandre de Moraes says two suspects had been identified but were not yet in custody.
"Our intelligence services are identifying those involved, two of them were already identified, and we will act quickly to arrest them."
The incident was the bloodiest of several that have marred the start of South America's first Olympic Games.
Over 85,000 security personnel -- double the number present in London in 2012 -- have been deployed to the city to keep thousands of Olympic athletes and an estimated 500,000 tourists safe.
