President Muhammadu Buhari says many black migrants claiming to be Nigerians even when they are not.
He said Nigerian embassies in North Africa were now overworked, trying to identify the true Nigerians.
His spokesman Mr Femi Adesina quoted him as saying this at the State House Abuja Tuesday while receiving Hon. Louise Mushikiwabo, Rwandan Minister of Foreign Affairs, who came as Special Envoy of President Paul Kagame.
"I don't envy our position, as many Blacks claim to be Nigerians, even when they are not," the president said.
Buhari said rather than dare the Sahara Desert and the Mediterranean Sea, with scores of lives lost in the process, illegal migrants should stay back home and find ways to improve their personal economies.
President Buhari said Nigeria had taken it upon herself to bring back thousands of her citizens now stranded in Libya.
"Illegal migration is now a major issue in Africa. Many dare the Sahara Desert and the Mediterranean Sea to get into Europe, and many die in the process. Or they get into trouble, as we now see in Libya.
"Most of the reasons they mention for migrating illegally are untenable. They should stay here, and see how they can improve their own economies, instead of risking their lives," he said.
Buhari said Kagame, as the incoming Chairman of African Union (AU), had the issues of South Sudan, separatist agitation in southern Cameroon, unrest in Togo, and many others on the continent, to contend with.
"Gaddafi's long rule produced many people, whose only skill is how to shoot guns. Now, they are scattered around the continent, still with their weapons, and fomenting trouble," President Buhari said, adding that Nigeria was taking steps to curtail the development.
Mushikiwabo said Kagame looked forward to the counsel and support of the Nigerian President, as he assumes the AU chair from this month.
"He will also need counsel on security issues in the Sahel, ongoing reforms in AU, borrow your expertise in agriculture, and renew friendship and kinship between our two countries," he said.