Islamist extremists

"Particularly worrying is the growing involvement of Islamist extremists, who profit both from experience in Iraq and supply lines to Iraq’s lawless Sunni regions. They had initially been marginal to Syria’s uprising, but locals now echo American diplomats’ suspicions that their foothold has widened. Last month a newly formed Jihadi group, Jabhat al-Nusra (the Salvation Front), released a professional video claiming past bombings against security forces. The attacks appear to have been carefully timed and skillfully executed."