^[1]Below is an extract from ASPI’s forthcoming publication Strike from the air: the first 100 days of the campaign against ISIL. Click here ^[2] to register for the publication’s free launch event.

The roots of ISIL ^[3] (PDF) can be traced to the al-Tawhid wa al-Jihad (Monotheism and Jihad) group established by salafi–jihadi Jordanian Abu Musab al-Zarqawi following the US invasion of Iraq in 2003. Zarqawi led a ruthless campaign of attacks across Iraq, directing suicide bombers to blow up mosques, schools, cafes and bustling markets, usually in predominantly Shia areas. Among its more high-profile attacks, al-Tawhid wa al-Jihad was responsible for attacks ^[4] against the Jordanian Embassy and UN headquarters in Baghdad, as well as the bombing of the holiest place of Shia worship in Iraq, the Imam Ali Mosque in Najaf.

In 2004, Zarqawi joined forces with al-Qaeda, renaming his group Al-Qaeda in Iraq (AQI). He continued his bloody campaign, but his ambitions were cut short when he was killed in a US airstrike in 2006. Zarqawi was replaced by Egyptian Abu Hamza al-Muhajir. Under Muhajir, AQI joined forces with other Sunni radicals and changed names again to become the Islamic State of Iraq (ISI), led by Abu Omar al-Baghdadi.

By 2010 ISI’s prominence in Iraq had been degraded, thanks to a forceful US counterterrorism campaign, Sunni tribal disaffection with AQI’s extremist ideology, and the deaths of both Abu Hamza al-Muhajir and Abu Omar al-Baghdadi in US airstrikes in 2010. It was at this point that US troops began withdrawing from Iraq and Abu Bakr al-Baghdadi took over leadership of ISI.

Capitalising on the instability in Iraq following the US withdrawal and extreme dissatisfaction among Iraq’s Sunni population with Prime Minister Nouri al-Maliki’s Shia-dominated governing coalition, Baghdadi revived Zarqawi’s brutal tactics and led a relentless campaign of suicide and car bombings. Baghdadi differed from his predecessor, however, in his targeting of not just Shia targets but also Iraqi police and military offices, checkpoints and recruiting stations.

ISI’s campaign proved attractive to many Iraqis who rushed to join its ranks. Many had either served as commanders and soldiers in Saddam Hussein’s military or, more unusually, been members of the secularist Baathist Party. ISI’s ranks swelled once again as a result of the group’s ‘Breaking the Walls’ ^[5] campaign, in which it attacked several Iraqi prisons. That included the notorious Abu Ghraib prison where between 500 and 1,000 prisoners, many of whom were extremists previously captured by the US, escaped in 2013. One of the escapees would later become one of ISIL’s top military commanders.

In 2011, ISI also commenced operations in Syria, where the uprising against President Bashar al-Assad had descended into civil war. ISI initially joined forces with local Islamist militants, most notably the al-Qaeda-affiliated Jabhat al-Nusra, but established itself as a force to be reckoned with in Syria in its own right after a split between the groups ^[6] (PDF), in which ISI commandeered much of Jabhat al-Nusra’s capabilities and many of its fighters. ISI made significant territorial gains in Syria between 2011 and 2013, fighting both government and rebel forces and establishing a stronghold in the northeast of the country.

It was at this point, in April 2013, that Baghdadi renamed his group ‘the Islamic State of Iraq and the Levant’ (ISIL). In January 2014, ISIL took control of Raqqah City in Raqqah Province. Its control of the city gave the group the ability to operate freely across the border into Iraq.

Analysts suggest ^[7] that ISIL is no simple terrorist organisation. Instead, it’s a functioning government with a hybrid terrorist-army, as convincing in insurgent techniques as it is in conventional warfare designed to conquer and govern large swathes of territory.

In early 2014, ISIL launched operations into Iraq, quickly taking control of the cities of Fallujah and Ramadi. However, it was in June, when ISIL seized control of Iraq’s second-largest city of Mosul—near the strategically important Mosul Dam—that the seriousness and scale of ISIL’s military operations became clear.

Since June, ISIL has taken over large swathes of land, controlling or contesting territory from Aleppo in Syria’s north to cities and towns close to Baghdad in central Iraq—territory roughly the size of the UK. The area is home to more than 6 million people—the population of Finland. By mid-October, ISIL had advanced to within 25 kilometres of Baghdad airport. It’s reported ^[8] that about a third of Iraq is dotted by active ISIL battle fronts. As the above map highlights, the scale and speed of ISIL’s military campaign in Syria and Iraq since January 2014 have been impressive.

Simone Roworth is ASPI’s Business Development and Budget Manager and a co-author of Strike from the air: the first 100 days of the campaign against ISIL. Image (c) Demap. Used with permission.