At least 18 people were killed in a police raid targeting organized crime groups in Rio de Janeiro's favelas, local Brazilian police said Thursday.

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

Some 400 officers were involved in the massive police operation, backed up by 10 bullet-proof vehicles and four helicopters.

Police often carry out raids in Rio's teeming slums in a bid to fight drug trafficking.

In May, 22 people were killed, also including a female bystander, in an early morning raid of the Vila Cruzeiro favela.

That came almost a year after Rio's deadliest police raid, in which 28 people were killed in the Jacarezinho slum.

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