A video has emerged on radical Islamist websites purporting to show the self-appointed leader of a newly proclaimed Islamic state in Syria and northern Iraq.
The video, posted Saturday, apparently shows Abu Bakr al-Baghdadi giving a sermon at a mosque in Mosul.
He appealed to his followers to help him if he is right, and put him "on the right track" if he is wrong.
Experts said it is likely the man in the video is the rarely seen Baghdadi.
Baghdadi's Islamic State of Iraq and the Levant (ISIL) fighters have seized large parts of northern Iraq, and are one of several radical Sunni Muslim groups fighting to overthrow the Syrian government.
Baghdadi has declared an Islamic "caliphate" in northern Iraq and Syria, calling on the world's Muslims to emigrate there and take up arms.
Some information for this report comes from AP and AFP.