At least 15 people died from floods in Adamawa state during the weekend and four others died in Niger state, the Daily Trust reported Monday.
Many other people have been declared missing, officials said.
The floods from torrential rains left more than 20,000 people homeless, officials said.
Adamawa State Emergency Management Agency official Shadrach Daniel said water from a dam flooded some areas.
"Farmlands, houses and livestock were affected by the flood, which was caused by the release of the water from Lagdo Dam and the heavy rainfall in the state," Daniel said.
"We are now going [around] the affected local government areas for proper assessment of the situation. All I could say is that the flood killed many people in the affected local government areas."
State Secretary Abubakar Ahmad said 13 of Adamawa state's 21 local government areas were affected by the floods.