Nigeria is battling its worst floods in a decade after heavy rains across the region.
At least 20 people died this week, according to authorities, and more than 300 people were killed in flooding incidents so far this year.
The floods have affected half a million people across 27 states, according to the National Emergency Management Agency.
Hundreds have been injured and some 100,000 people have been displaced, the agency added.
The disaster management agency is warning of "serious consequences" in the coming weeks as two dams have begun to overflow.
With just over 206 million people, Nigeria is Africa's most populous country.
Floodwaters have destroyed thousands of hectares of farmland, worsening fears of a disruption of food supplies.
They drowned crops across the northern region, which produces much of what the country eats.
This has raised concerns that it could further affect supplies already disrupted by armed conflict in the northwest and central regions.
The Nigeria Hydrological Services Agency predicts more floods in 2022 than last year due to "excessive rainfalls".