More than 150 people were feared dead in northwest Nigeria on Wednesday after an overloaded boat ferrying about 200 passengers to a market sank within the Niger, local officials said.

When the boat sank it had been traveling between central Niger state and Wara in northwest Kebbi state, National Inland Waterways Authority local manager Yusuf Birma informed reporters.

Birma said, “The boat capacity wasn’t up to the 180 passengers it carried. As we speak, only 20 people are rescued alive, four dead confirmed while the remaining 156 people are still missing and that they are believed to be underwater.”

Nigerian President Muhammadu Buhari offered his condolences to families and said the accident was “devastating.” But his statement didn’t give any official total of the number of casualties.

Boat accidents are common on Nigerian waterways mostly thanks to overcrowding, inclemency, and lack of maintenance, but Wednesday’s toll would be one among the deadliest recent accidents. Earlier this month, 30 people died when an overloaded boat capsized in Niger state.

The Niger is West Africa’s main river running during a crescent through Guinea to Nigeria’s Niger Delta and is a key local trade route for a few of the countries.