The surprise offensive by a hardline militant group in Syria has raised fears of a second Islamic State, but the man leading the charge appears to have a different vision

One of the oldest cities in recorded history, Aleppo, was seized by the Islamist group Hayat Tahrir al-Sham (HTS) on November 30. Leading the HTS was Abu Mohammed al-Jawlani, a man on who the US has put a $10 million bounty on his head, as well as a man who was given the tag of an apostate by the Islamic State.

Islamist-led rebels advanced on Syria's fourth-largest city Hama Tuesday, buoyed by their lightning capture of swathes of the north in an offensive that ended four years of relative calm.

Government forces, backed by Russia, have been fighting with rebels fiercely for control of the key city. The clashes have been the "most violent" since the recent flare up in the Syrian conflict.