There are approximately 5000 Sunni foreign fighters in Syria. These fighters join battalions, also known as ‘muhajireen’ units, which in turn mostly support either the Islamic State of Iraq and the Sham (ISIS) or Jabhat al-Nusrah (JN).  This general profile focuses on three battalions: Katiba al-Bittar al-Libi, Katiba al-Muhajireen, and Imam Bukhari Battalion