Members of the group interviewed by Reuters say al-Nusra aims to revive the Islamic Caliphate, which dates back to the Prophet Mohammad’s seventh century companions, forerunners of the large empire that once stretched into Europe.

That prospect alarms many in Syria, from minority Christians, Alawites and Shi’ites to traditionally conservative but tolerant Sunni Muslims who are concerned that al-Nusra would try to impose Taliban-style rule.

Fear of religion-based repression has already prompted Kurds to barricade their quarter of Aleppo city and was behind fierce clashes between Kurdish and al-Nusra fighters in the border town of Ras al Ain in November.

The ideas of al-Nusra are also at odds with a new Syrian opposition coalition that was recognized last week by dozens of countries as an alternative to Assad and is committed to establishing a democratic alternative to Assad’s rule.