Boko Haram, the Nigeria-based terror group, has pledged allegiance to ISIL, according to an audio message purported to be from Boko Haram’s leader, Abubakar Shekau

Boko Haram, the Nigeria-based terror group, has pledged allegiance to ISIL, according to an audio message purported to be from Boko Haram's leader, Abubakar Shekau.

In the audio, which was posted online Saturday, the speaker says Boko Haram is announcing its "allegiance to the Caliph of the Muslims, Ibrahim ibn Awad ibn Ibrahim al-Husseini al-Qurashi," which is another name for ISIL leader Abu Bakr al-Baghdadi.

The pledge follows a period during which Shekau's faction had been mimicking ISIL, including praising al-Baghdadi and featuring his image in their videos and photos.

ISIS leaders view Shekau as inferior, partly for racist reasons, the CIA indicated at a briefing for reporters.