The International Committee of the Red Cross, ICRC, said almost 22,000 people are missing in the Northeast as a result of the Boko Haram insurgency.
The humanitarian agency said the figure is the highest number of missing persons registered in any country.
In a press release, the agency also says nearly 60 per cent of the total were minors at the time they went missing. This means thousands of parents do not know where their children are and if they are alive or dead.
The Global Terrorism Index ranked Nigeria as the third most terrorised country in the world, for the fourth consecutive year in 2018
The ICRC underscores the immense challenges that come with finding missing people and reconnecting them with their families in Nigeria.
It said 367 cases have been solved since 2013.