The states that may be affected are: Adamawa, Taraba, Benue, Nasarawa, Kogi, Anambra, Edo, Delta, and Bayelsa states.
Ahmed said the recent release of water by the dam has led to the displacement of 48,100 persons in 13 states of the federation and could lead to the destruction of crops and other infrastructure.
He added that since August 14 when the dam was opened, 28 deaths have been recorded and 159,157 persons have been affected.
The NEMA DG called on all heads of State Emergency Management Agency (SEMA) to cushion the effects of the disaster.
He said: “NEMA has been alerted on sudden increased inundation of riparian communities and farmlands along the banks of River Niger in Adamawa, Taraba and Benue states in the past 48 hours.
“The sudden situation is attributed to the rapid release of waters from Lagdo Dam in the Republic of Cameroon and has resulted in the displacement of several inhabitants of the affected communities.
“Furthermore, croplands and valuable infrastructure are at risk of getting washed away by the flood waters. Situation reports from Adamawa State confirm the upsurge of flood waters along the flood plains of River Benue.
“The situation is expected to be replicated in downstream states of Taraba, Benue, Nasarawa, Kogi, Anambra, Edo, Delta and Bayelsa as the River Benue joins River Niger and flows to the Atlantic Ocean through the Niger Delta.”