At least 18 people have been killed in a police raid targeting organised crime groups in Rio de Janeiro's favelas, local Brazilian police said.

A law enforcement officer and a woman who lived in the area were among the 18 people who died in the Complexo do Alemao slum, while the 16 others are believed to be members of organised crime groups, a police spokesperson told a press conference on Thursday.

Tactical teams from Rio de Janeiro's civil and military police raided the Alemao complex to take down an alleged criminal organiSation suspected of involvement in cargo theft and bank robberies which was planning incursions into rival slums, the military police said in a statement.

It said around 400 officers were involved, with support from four aircraft and 10 armored vehicles.

Rio state police forces regularly carry out deadly raids in the city's sprawling slums. 

President Jair Bolsonaro has long supported heavy-handed tactics by police in their fight against organised crime, saying gangsters should "die like cockroaches."

"There are signs of major human rights violations, and the possibility of this being one of the operations with the highest number of deaths in Rio de Janeiro," the state public defender's office said in a statement.

READ MORE:Casualties as Brazil favela raid turns bloody

'If they want a war, send them to Iraq'

After the raid, locals could be seen bundling injured people into the back of vehicles to be taken to the hospital as police watched. 

Gilberto Santiago Lopes, from the Anacrim Human Rights Commission, said the police refused to help.

"We had to carry them away in a beverage truck, and then flag a local resident in their car to take them to hospital," he said. 

"(The police) don't aim to arrest them, they aim to kill them, so if they're injured, they think they don't deserve help."

The military police declined to comment beyond its statement.

Local residents were furious and yelled at the police.

"We're scared to live here," one local screamed after the raid. 

"Where are we? Afghanistan? In a war? In Iraq? If they want a war, send them to Iraq."

READ MORE: Brazil police accused of rights abuses after shootout in Rio slum