A boat with 110 people aboard sank in the Brazilian Amazon on Sunday, killing at least 12 people and leaving dozens missing, AP quoted authorities as saying. The Comandante Sales capsized before sinking swiftly on the Solimoes River, one of the largest branches of the Amazon, Fire Lt. Col. Raimundo Rodrigues da Silva said. The vessel was carrying passengers who were returning from a party near the jungle city of Manaus, he said. It was not clear what kind of boat the Comandante Sales was or how many passengers it was equipped to carry. The bodies of 10 women and two men were recovered and several dozen people were unaccounted for, Silva said. The victims had not been identified and it is unlikely the boat kept a passenger list, he said. It is possible the vessel was overloaded, but the cause of the sinking was still being investigated, Silva said. He added that passengers may have been trapped inside the boat because many were sleeping when it went down. Local news media reported that some passengers survived by swimming to shore, but Silva said authorities did not have a survivor count. The Brazilian navy joined about 45 rescue workers, including 15 divers, in the search for victims and survivors.