The abduction of more than 200 schoolgirls in Nigeria last month was "contrary to the teachings of Islam", the head of the African Union (AU) said at an event to mark Africa Day on Sunday.
"We strongly condemn the abduction of the young, innocent schoolgirls in Nigeria.
"We urge their immediate unconditional release," said Mohamed Ould Abdel Aziz, who is also president of Mauritania, in a message to Africans sent out over the weekend.
"These actions are contrary to the teachings of Islam, a religion of tolerance and peace," he said, marking the 51st anniversary of the creation of the Organisation of African Unity, the predecessor to the AU.
The Islamist group Boko Haram has claimed responsibility for the mass abduction on April 14 in Chibok, in northeast Nigeria.
It has carried out a brutal insurgency in the region since 2009, that has claimed around 2,000 lives this year alone.
"The situation in Mali, in Nigeria, in the Central African Republic, in Somalia, in South Sudan and in Libya challenges us and deserves all of our attention," said Abdel Aziz.
The president also used the speech to call for reform of the United Nations.
"Africa relies on its partners to help meet the challenges of underdevelopment. Reform of the UN system, in the sense of enhancing the role and weight of Africa, is necessary."
He said "food self-sufficiency, the development of agribusiness and the fight against poverty and malnutrition" were key priorities for the AU.
On the economic front, he celebrated the "strong growth in the continent", which is "immensely rich and young, with enormous potential", and called for the creation of "a strong continental free trade zone of more than a billion consumers".