Rio de Janeiro  - At least nine people were killed in a police raid on the slum Vila Cruzeiro, in the northern outskirts of Rio de Janeiro, Brazilian media reported Wednesday.

The authorities said all the dead in the raid - which started on Tuesday morning and lasted over 12 hours - were alleged criminals who had set up barricades to prevent police officers from entering the favela (slum).

Some 180 officers of the Brazilian militarized police, including elite squads, took part in the raid, which also led to the arrest of 15 suspects.

The violent shootouts in the framework of the raid also wounded six residents of the slum who apparently had no ties to criminal activities.

"The operation was successful," Rio state Security Secretary Jose Beltrame was quoted as saying.

In early April, 11 alleged criminals were killed in a police raid on two slums of Rio.

Police operations on the city's favelas are controversial, and residents and human rights organizations denounce that in almost all cases innocent people get hurt, sometimes including children.(dpa)