Nigeria kidnappings barbaric: Islam chief

OIC secretary-general Iyad Madani says the kidnapping of more than 270 Nigerian schoolgirls is "barbaric" and "inhumane".

A massive assault by Boko Haram in northeast Nigeria has displaced more than 15-thousand people. (AAP)

The secretary-general of the world's largest bloc of Islamic countries says the kidnapping of more than 270 Nigerian schoolgirls is a "barbaric" and "inhumane" act.

The kidnapping by the extremist group Boko Haram in Nigeria has prompted worldwide condemnation.

The group claims to use Islamic teachings as justification for threatening to sell the kidnapped girls into slavery.

"This is inhumane and barbaric," Iyad Madani told The Associated Press on Saturday from the Organization of Islamic Cooperation's headquarters in Saudi Arabia in his first interview with the media since officially taking office in January.

He said such extremist groups "not only disavow their Islam, but also their humanity".

Madani says sectarian violence is among the most important challenges facing the Muslim world.

The OIC is comprised of 57 Muslim-majority member states.