The sources disclosed that the girls were picked up by military helicopter from Banki area of Borno state where Boko Haram militants dropped them off earlier today.
The release of the 21 girls comes as President Buhari began a three-day trip to Germany to discuss assistance for the rebuilding of the northeastern part of Nigeria ravaged by Boko Haram.
Military chopper has evacuated the released girls to a medical facility for evaluation.
The release of 21 Chibok girls was brokered by International Red Cross and the Swiss government, according to the Presidency.
