At least 15 people have died and more than 100 others are missing after a convoy of three boats capsized on the Congo river in the western part of the country early Tuesday.

Passenger logs showed the boats were carrying 260 people, Ngiam Kipoy, responsible for lakes and rivers at the country's transport ministry, told the German Press Agency on Wednesday. More passengers could have been on board, he said, as operators often overpack them.

Local reports have put the number of passengers at 500.

Kipoy said the accident occurred near the village of Kwamuth, and that some survivors managed to swim to safety.

Accidents are common on Congo's overcrowded boats, which are a key means of transportation because of the country's poor road infrastructure.

In 2014, more than 100 people died when a boat capsized on Lake Tanganyika.