Flooding has become a national disaster in four states of Kogi, Niger, Delta and Anambra, according to the Director-General of the National Emergency Management Agency (NEMA), Mustapha Maihaja.
The agency further placed eight other states on its watch list.
The declaration was made on Monday by NEMA days after the President ordered the agency to declare the situation a national disaster.
Following the order, Maihaja had earlier inaugurated five Emergency Operation Centres (EOC) to facilitate prompt search and rescue operations as well as humanitarian support in the 12 states worst affected by flooding.
The Emergency Response Centres will be responsible for planning, organising, directing and supervising deployment of resources with the affected state governments and local authorities and communities.
The primary objective is to localize the responses and expedite intervention to save lives and facilitate quick recovery.
At the command centre in Abuja, the NEMA DG and other chief executives will be responsible for the formulation of policy and operational guidelines for the conduct of emergency operations in all the worst affected states.