Bodies piled up in poor neighborhoods of Rio de Janeiro on Tuesday as police launched their biggest ever raids on the city's drug traffickers, leaving at least 64 dead in war-like scenes.

As many as 2,500 heavily armed officers, backed by armored vehicles, helicopters and drones took part in the operation targeting Brazil's main drug-trafficking gang in two poor neighborhoods, or favelas, in northern Rio.

Gunfire rang out in the area near Rio's international airport, and smoke billowed from several fires on Tuesday afternoon, several hours after the raids started.