Some 500 Nigerian migrants have been sent home from Morocco where they had been living in forests.
Migrants hide in the forests until they are ready for the risky crossing into Spain
The migrants were flown from the central city of Fez to discourage illegal entry into Europe.
Most of those repatriated had run out of money to pay people smugglers to continue their journeys.
This is the third such operation carried out jointly by Nigeria and Morocco in recent months, according to the Nigerian Embassy in Rabat.
Morocco is the staging-post for illegal migrants from Nigeria, Gambia, Guinea , Mali and Senegal hoping to enter Europe through Spain.
The latest group comprised 313 men and 160 women and some small children believed to have been born in the forests.
The BBC's Pascale Harter in Rabat, says most of the migrants volunteer to return home instead of living tough in the forests near the Spanish enclaves of Ceuta and Melilla on the Mediterranean coast.
Last month 657 Nigerians were repatriated on two flights from Oujda and Nador in northern Morocco.
The migrants travel in vehicles and on foot across the Saharan regions of Niger, Mali and Algeria before crossing the Mediterranean Sea into southern Spain.
More than 17,000 illegal migrants were intercepted this year while attempting to enter Spain by sea.