A year after the world applauded Rio's successful staging of the Olympics, Brazil's second biggest city is in deep financial difficulty.
In the third such operation in just over two weeks, marines, army soldiers, air force personnel, police and agents from the elite federal intelligence service launched raids at dawn in seven neighborhoods, the Rio state security office said.
A year after the world applauded Rio's successful staging of the Olympics, Brazil's second biggest city is in deep financial difficulty and the demoralized police are struggling to contain well-armed drugs gangs based in the favelas.
Targets of Monday's raids included the notorious Complexo do Alemao -- a dense maze of warrens where police rarely venture -- and Jacarezinho, where seven people have been shot dead just in the last 10 days.
The state security service said in a statement that the principal goal was to serve arrest warrants.
"Teams from the armed forces are responsible for guarding perimeters in some of these regions and basing themselves at strategic points to guarantee order," the statement said. "Some roads are closed and the airspace is restricted for civil aviation."
According to Globo news organization, police were looking for 14 people, all of them drug trafficking suspects with street names including "Bamba," "PH" and "Indio do Mandela," or "Mandela's Indian."
President Michel Temer's decision in July to send in the military to Rio acknowledged that state police have lost the ability to cope with the often bloody struggle against the drug traffickers. Nearly 100 police officers have died this year alone.
Corruption has also hampered police operations. In June, arrest warrants were issued for 185 police officers after a lengthy probe accused them of collaborating closely with drug gangs, even renting out automatic weapons to the gunmen.
The military is often cited as the national institution most respected by Brazilians. Memories of the 1964-1985 military dictatorship are fading and the armed forces is seen as largely having kept out of the corruption riddling Brazil's government at every level.
However, despite that clean image, Globo reported that a 19-year-old soldier had been arrested Monday on suspicion of having tipped off gangs several hours before the operation took place.
Globo quoted police saying that traffickers had been heard warning each other by radio during the night "to disperse."
In the first half of this year Rio tallied 3,457 homicides -- the highest level of violence since 2009 and 15 percent more than during the same period in 2016.