The United Nations Children's Fund, or UNICEF, is calling on the international community for support for an estimated 4 million people, including many children, in western and central Africa who have been affected by a spate of severe flooding.

The UN agency says these people have lost their homes or have otherwise suffered damage from flooding this year.

UNICEF is calling for aid amid mounting concerns about a possible outbreak of infectious disease among children due to deteriorating sanitary conditions.

It notes that children also need support because the damage to schools has taken away their opportunity to study.

In Nigeria, heavy rainfall since late August caused a dam to collapse, leading to extensive overflow of river water into a wide swathe of urban areas. The country's government says at least 37 people have died. Rescue operations are still underway.

In neighboring Chad, a series of floods have hit many places across the nation since July. The UN says 145 people have been killed and more than 160,000 homes have sustained damage.

Flood damage has also been reported in other countries in the region, including Mali and Niger.