Al Qaeda's rise in Syria It has become a challenge to define who are the fighting forces in Syria. Syrian Armed Forces personnel who deserted, along with volunteers, call themselves the Free Syrian Army. But there are numerous other insurgent groups. It is also complex to identify those from other countries, and what they hope to achieve. Islamic radical Salafist and Jihadist fighters have been active in Syrian territory since 2011, and steadily infiltrated the uprising against the Bashar al Assad regime. They came from Lebanon, Jordan, Iraq, the Gulf states and Arab countries in North Africa, vowing to fight their cause against those they call the Infidel. Among the most effective rebel force is the Sunni Islamist and Jihadist al Nusra. The full form of its name means: "Supporters of the Front for Victory of the People of Syria." It wants a Pan-Islamic state under Sharia law here. It is also anti-Western, not just anti-Assad, and has been designated as a terrorist organisation by the US. An al Nusra commander says: "We are against the regime from the bottom of our hearts. When the so-called Arab Spring started, we were the first to join the revolution. The new leader of the global militant Islamist organisation al Qaeda months ago called for its faithful to do service in Syria. Ayman al-Zawahri made his aims clear: "Our people in Syria don't rely on the West or the United States or Arab governments and Turkey. If we want freedom, we must be liberated from this regime. If we want justice, we must retaliate against this regime. Many Syrians welcome the presence of outside militants working to remove Assad. The slogan at a support rally last Friday was: "The only terrorism in Syria is Assad's terrorism," which seemed a direct challenge to American labelling of al Nusra. To learn more about the role of al Qaeda in the Syrian conflict, we spoke with Dr Vali Nasr, Dean of Johns Hopkins University's School of Advanced International Studies in Washington. Nik Martin, euronews: "The media has explained the Syrian uprising in very simplistic terms, as "Assad versus the rebels." But, with Al Qaeda now seen as playing a role in the crisis, how exactly do they fit in, and why has their involvement been mostly ignored up to this point? Dr Vali Nasr: "Well al Qaeda was involved in the conflict from the very beginning. Some of the cells came from Iraq, they set up shop in Syria, they were very effective in the fighting. They have a lot of access to weaponry and cash, and they use that to expand their network. And now they are part of the fighting across the country that actually is dominated by al Qaeda and therefore they are a very big part of the military opposition to the Assad regime on the ground. We ignored that largely because there were very little evidence of it and also because the international community was focused on Assad rather than on the make-up of the opposition. euronews: "So who exactly are these people and who is coordinating them? " Dr Nasr: "We don't know about who's coordinating them but we know that many of the original al Qaeda fighters came from Iraq. They belong to the networks that had operated against the US troops in Iraq. Others have probably joined them from the outside. There was always a number of Syrians that were involved in al Qaeda from the very beginning, going back to the events of 9/11. In Syria, they decided to distance themselves from al Qaeda, they took the name of Front for Victory or "Jabhat al-Nusra" and began to position themselves as a legitimate anti-Assad resistance group and it was only with time that it became clear that this is al Qaeda, except that it has decided to position itself in a way that would make it much more of a legitimate opposition to the Assad regime." euronews: "And how decisively are they influencing the rebels" tactics?" Dr Nasr: "They are quite an important force among the rebels, because they have very good caches of arms, they have used their access to arms, particularly earlier in the conflict to build relations with other rebel groups and to be able to co-opt many of them and bring them under their own umbrella. In some part of Syria the main fighting force is al Qaeda and in other parts they are a junior partner to the fighting. But that's not all. Al Qaeda doesn't require an enormous amount of territory in order to organise or amount of explosive capability to be effective, and, therefore, given the chaos in Syria, al Qaeda units have found ample room to organise, recruit, build their capabilities and to be able to carry out varieties of operations. euronews: "So with al Qaeda playing such a pivotal role, how much influence does the West have into what is going down in Syria right now?" Dr Nasr: "In Iraq we were able to flush out al Qaeda because we had a large American troop presence that was able to carry out special forces operations, decapitate al Qaeda, create relations with local tribes in order to push them out of the territory. That kind of resistance to al Qaeda does not exist in Syria. The Assad regime is fighting against them, but the Assad regime is shrinking its footprint, so it's a very dangerous situation in which al Qaeda, that was almost extinguished in Iraq, has found new territory and new opportunity to begin to expand again. More about: Al-Qaeda, Armed conflicts, Bashar al-Assad, Islamists, Syria