The wooden ferryboat, which was carrying at least 80 passengers, most of them young people returning from a party, sank after a rainstorm in the Solimoes River early on Sunday. The boat had a capacity of 50 people, officials said.
Rescuers have so far recovered 16 bodies, and a search for the others is underway. Local officials and witnesses claimed some of the passengers managed to swim to the river bank.
The ship had been grounded by authorities in mid-January after an inspection revealed that the vessel's crew lacked the appropriate qualifications.
In February, another wooden ferry, carrying more than 100 people, sank near the isolated town of Itacoatiara in the state of Amazonas after a collision with a barge, leaving 16 people dead.
