Beirut: The chief of al-Qaeda's Syrian affiliate says the self-proclaimed caliphate of Islamic State is "illegitimate" and its fighters have strayed from the path of Islam.

In the second part of his appearance on the Qatari-owned al-Jazeera news channel, Nusra Front leader Abu Mohammed al-Golani criticised IS at length and said he did not foresee a reconciliation between the two extremist groups.

A member of al-Qaeda's Nusra Front during an offensive against forces loyal to Syrian President Bashar al-Assad. Credit:Ammar Abdullah

"They announced a caliphate, but the scholars rejected it as illegitimate. It is not based on Islamic law," Golani said, his face hidden from view by a black scarf.