""Those battalions, which include Nusra and another Islamist
brigade, Ahrar al Sham, have been at the forefront of the fighting across Syria.
More moderate Islamist groups, such as the Farouq Brigades and Liwa Tawhid, both
of which are believed to be allied with the Syrian Muslim Brotherhood, also
operate across the country. Nusra is believed to have as many as 5,000 men under
arms, and Sham is thought possibly to be larger, making the Islamist-led groups
the largest fighting organizations of the multi-faceted Syrian opposition."" (thanks Amir)