By December 2015, the Islamic State covered a vast landlocked territory in western Iraq and eastern Syria, with a population estimate of 2.8 where it enforces its interpretation of sharia law.
Other reports, however, have indicated that Syrians are at a disadvantage to foreign members, with some native Syrian fighters resenting "favouritism" allegedly shown towards foreigners over pay and accommodation.
In August 2016, media reports based on briefings by Western intelligence agencies suggested that ISIL had a multilevel secret service known in Arabic as Emni, established in 2014, that has become a combination of an internal police force and an external operations directorate complete with regional branches.
Participant in the Iraq War (2003–2011), Iraqi insurgency, Syrian Civil War, Iraqi Civil War, Second Libyan Civil War, Boko Haram insurgency, War in North-West Pakistan, War in Afghanistan, Yemeni Civil War, and other conflicts ISIL originated as Jama'at al-Tawhid wal-Jihad in 1999, which pledged allegiance to al-Qaeda and participated in the Iraqi insurgency following the 2003 invasion of Iraq by Western forces.
The group proclaimed itself a worldwide caliphate In Syria, the group has conducted ground attacks on both government forces and opposition factions.
ISIL has also attempted to present a more "rational argument" in a series of videos hosted by the kidnapped journalist John Cantlie.
In one video, various current and former US officials were quoted, such as US President Barack Obama and former CIA Officer Michael Scheuer.
Such symbolism has been said to point to ISIL's belief that it represents the restoration of the caliphate of early Islam, with all the political, religious and eschatological ramifications that this would imply.
For their guiding principles, the leaders of the Islamic State ...
Following the plan of al-Qaeda strategist Abu Bakr Naji, ISIL hopes the "savagery" will lead to a period of "vexation and exhaustion" among its Western enemies, where the US will be drawn into a direct fight with ISIL, and lacking the will to fight a sustained war will be "worn down" militarily.