It is almost four years since the Syrian uprising began amid the optimism of the Arab Spring. It has degenerated into a savage civil war that has killed over 200,000 people and shattered the lives of millions more.

It has also seen thousands of young Muslims from Europe, Australia and elsewhere travelling to Syria to fight - many joining competing groups such as the Islamic State of Iraq and the Levant (ISIL) and Jabhat al-Nusra, al-Qaeda's Syrian arm, which, as well as seeking the overthrow of the Assad regime in Damascus, are locked in their own intense battle for the hearts and minds of the local population.

For this exclusive People & Power report, Danish filmmaker Nagieb Khaja went to Syria to speak to Western fighters and to one of Jabhat al-Nusra's senior figures - the Australian / Egyptian cleric, Abu Sulayman Muhajir. In this remarkable film, made possible through long and patient negotiation for access, Nagieb finds out why young foreign Muslims are being drawn to the conflict in Syria, explores the reasons behind Jabhat al-Nusra's fierce rivalry with ISIL and examines the implications of these developments for global security.

FILMMAKER'S VIEW

By Nagieb Khaja

In May 2014, I met a group of foreign fighters in northern Syria who introduced me to members of Jabhat al-Nusra, the local al-Qaeda franchise. I immediately began to negotiate access to film with them. Nusra is one of the most powerful, and certainly the most secretive rebel group in Syria. It shares its roots with ISIL.

Key members of both groups fought in the brutal Iraqi insurgency of the 2000's, and ISIL and Nusra were initially close allies, fighting under the al-Qaeda banner. But then in mid-2013, a violent conflict over territory and ideology erupted between the two groups. This local dispute has huge implications for global security, with different jihadist groups around the world pledging allegiance either to al-Qaeda or ISIL. The footage I shot with Nusra provides a fascinating insight into al-Qaeda's vision for the future of Syria, and its strategy for beating ISIL in the battle for hearts and minds in the region and beyond.

ISIL's spectacular military victories and its declaration of a caliphate drew thousands of defectors from other groups. But while the media has focused on the territory ISIL holds in the east, al-Nusra and its allies have quietly been building their own Islamic State in northwest Syria.

Negotiations to film took several months, but finally, the group's leader, Abu Muhammed al-Jowlani, sanctioned an interview with one of their senior officials, Abu Sulayman Muhajir. An Australian of Egytian descent, he is a high-ranking member of Nusra's Sharia council, and served as a mediator between al-Qaeda and ISIL when the two groups split. He eventually sided with Nusra - releasing videos on jihadi internet forums in which he publicly accuses ISIL leader, Abu Bakr al-Baghdadi, of breaking a sacred oath to al-Qaeda's head, Ayman al-Zawahiri.

Some analysts believe that Jabhat al-Nusra and ISIL are essentially the same, but my experience on the ground, and my conversations with Nusra members, from foot-soldiers to those in leadership positions, convinced me that there are profound differences between them. Both ISIL and Nusra subscribe to a fundamental version of Islamic law, but it is in the interpretation and implementation that they vary.

Abu Sulayman told me that contrary to ISIL, which has declared itself the only legitimate Islamic authority, Nusra sees itself as part of a wider movement that works with other Islamic groups. He said that Nusra regard ISIL as a criminal group that has gone astray from Islamic law, and that they would only reconcile with them if they repented and accepted judgement in an independent Islamic court. For example, Abu Sulayman criticises ISIL's killing of western aid workers, calling such acts crimes under Sharia.

Nusra is fighting the Assad regime in Syria, but at the same time Abu Sulayman told me that they are fighting for an Islamic revival in the Middle East, with the ultimate goal of establishing their own caliphate. And as a branch of al-Qaeda, he confirmed that they see the US and its allies' meddling in the Muslim world as an obstacle to their goals, and are therefore a part of the wider conflict with the West. "Their choice is simple," he told me. "Leave our lands, stop interfering in our affairs or face perpetual war."

When the US began targeting ISIL with airstrikes in September 2014 they also hit Nusra units. The US denied attacking Jabhat al-Nusra, however, claiming they had only hit the so-called Khorasan Group - an al-Qaeda cell which the White House alleged was dedicated to planning attacks on US soil. Abu Sulayman refused to comment on this, however, citing security reasons.

Whatever the truth about the Khorasan Group, immediately after the strikes, Nusra moved against the US' last remaining allies in region - two relatively secular rebel groups which the US has armed and trained, the Syrian Revolutionary Front and Harakat Hazm. The Syrian Revolutionary Front was quickly defeated and expelled from Syria, and just a few days ago Nusra declared victory over Harakat Hazm, taking over their territory and seizing their US supplied weapons.

It is yet another setback for US strategy in the region. Nusra have further consolidated their hold over northwest Syria, and plan to be there for the longterm.

Source: Al Jazeera