A boat carrying more than 80 people sank on Sunday at dawn on a major river in the Amazon rain forest, rescue workers and media reports said.
The boat sank before 6 a.m. on the Solimoes River, about 50 miles (80 km) from Manaus, a spokesman for the city's fire department told Reuters.
It was returning an estimated 80 revellers from a party in the interior of the state, he said.
According to CBN radio, as many as 150 people were on board the boat, which had a capacity of 50 people. Twelve bodies were found and more than 40 are missing, CBN said.
Forty fire workers and 15 divers were participating in the rescue operation, which could take several days in the silty river, the spokesman said.
Boats travelling on the many rivers in the Amazon region are frequently loaded beyond capacity and are seldom controlled by authorities.
