At least 18 people have been killed in clashes between police and gangsters in a slum in the Brazilian city of Rio de Janeiro, authorities have said.
Guns and grenades were used in the fighting, with armoured vehicles and helicopters backing police units.
The violence reportedly began when more than 1,000 policemen advanced on the slum stronghold of a drug-dealing gang.
Rio de Janeiro officials are trying to make the city safer before it hosts the Pan-American games on 13 July.
Some 5,500 athletes and around 800,000 tourists are expected to visit the city for the games.