The vessel, which was heading to the capital Kinshasa from the port of Bena Dibele — a journey of more than 800 kilometers (497 miles) — sank late Monday after being caught in strong whirlwinds, according to UN radio.
Local administrator François Ahoka said the boat was carrying roughly 120 passengers.
“About 50 people have been rescued so far, and search efforts continue for those missing,” he said, noting that rescue teams are struggling with difficult conditions.
Ahoka urged families to remain in contact with local authorities to help identify survivors and bodies recovered from the river.
Boat accidents are common in the DRC, where poor infrastructure and impassable roads force many communities to rely heavily on river transport.