Heavy rains and flooding in 12 states deemed a national disaster with hundreds of thousands facing a cholera outbreak.

Nearly 200 people have died in flooding caused by heavy seasonal rains across 12 states in Nigeria.

The National Emergency Management Agency (NEMA) said on Thursday that 199 people were killed after the main Niger and Benue rivers burst their banks.

A national disaster was declared in several central and southern states.

The United Nations last week said there had been more than 3,000 recorded cases of cholera and 97 deaths in the northeastern Nigerian states of Borno and Yobe in the past two weeks alone.

NEMA said in its latest update that “large-scale flooding” since late last month made more than 286,000 people homeless.

Numbers were expected to rise and more rain is expected in the coming weeks, it added.

Shelter, food, medicine and other items such as mosquito nets were “priority needs”, the report said.

Flooding has not only devastated towns and villages along the rivers but also destroyed crops and killed livestock, said Abubakar Kendehe, secretary-general of the Nigerian Red Cross.

“One of our biggest concerns following extensive floods like this is the threat of cholera and other diseases,” Kendehe warned.

Lack of sanitation, healthcare and clean water “could have deadly consequences” and add to the nearly 28,000 suspected cases of cholera reported across Nigeria since January, he said.

In the wider Lake Chad region – comprising Nigeria, Niger, Chad and Cameroon – more than 500 people have died from the water-borne disease since the start of the year.

Northeast Nigeria has also been the epicentre of Boko Haram’s attacks, which have killed more than 20,000 people since 2009.

Some 1.8 million are still homeless there, many living in makeshift camps as a result of the conflict.