The central African nation has a history of deadly boat accidents, often attributed to overloading. In June, a similar incident occurred near the capital, resulting in 80 fatalities.
A motorized wooden boat carrying approximately 300 passengers collided with a submerged barge on the Lukeni River during a night journey, territory administrator Jacques Nzenza Mongie said at a news conference.
Despite nighttime navigation being illegal in Congo, the boat was traveling when the accident occurred.
At least 20 bodies were discovered on Tuesday, and 46 people were rescued, with hundreds still missing, according to Mongie.
A provincial commission is investigating the incident to identify those responsible, while Gov. Lebon Nkoso Kevan of Maï-Ndombe province reaffirmed commitments to enforcing water transportation safety and preventing overloading.