At least 10 people have been killed and six injured in a shootout between the Brazilian police and drug traffickers on the outskirts of this city, the EFE news agency reported Tuesday.

The incident took place in Lagoinha slum on the western part of the city Monday. The police were investigating a case in the area when gunmen opened fire at them.

The victims belonged to a gang of drug traffickers, the police said. Six people, including a policeman, were injured in the shootout.

The authorities have seized a huge cache of weapons from the site. Gunfights between the drug mafia and the police are common here - considered one of the most violent cities in the country.

According to an official estimate, at least 1,330 people belonging to various gangs have been killed in clashes with the police last year. In the first five months of 2008, some 649 people have been killed already.

'I can say that machine guns in the hands of drug traffickers is very dangerous,' head of the Rio de Janeiro police (drug squad) Carlos Oliveira said.