At least 13 people drowned when a boat capsized earlier today on a tributary near the mouth of the Amazon river in Brazil. Most of the passengers were asleep below-deck when the overcrowded boat flipped over, due to strong river currents.

Rescuers picked up 46 survivors. Divers are currently searching the hull of the sunken vessel for a least a dozen people who are still missing. Military police Sargent Orivaldo Santos said that divers are uncertain of how many people are unaccounted for:

"We don't know how many people are missing because the captain doesn't know how many were on board."

The boat had a capacity for 25 passengers, but the captain told the police that there were more than 60 aboard. The boat was on the way to the Brazilian city Belém from Marajo Island. The travelers were most likely on their way to a market there to sell shrimp, açaí, and fruit.

[Reuters, image via thobo/Shutterstock]