In June 2014, the Islamic State (also known as ISIS or ISIL), which had controlled a large portion of Northeastern Syria at that time during the Syrian civil war, launched a full-scale invasion of Iraq, capturing a large swath of territory extending all the way from the Iraq–Syria border to the outskirts of the Iraqi capital city of Baghdad. The invasion came after months of clashes in Anbar province, where tribal groups, and some extremist factions—which had pledged allegiance to ISIL—had been fighting Iraqi government forces in the cities of Fallujah and Ramadi following a series of anti-government protests. The offensive led to the occupation of 40% of Iraq’s territory by the Islamic State, the collapse of several elements of the then-corrupt Iraqi Army and the genocides and mass killings of various religious groups, such as the Yazidis, Christians and Shia Muslims (who form a majority in the country). This event led to the intervention of Iran and the United States in assisting Iraq in its conflict with the Islamic State, with the latter providing assistance to both Iraqi and Kurdish forces.
The Islamic State of Iraq and the Levant and its allies captured several cities and surrounding territory, beginning with an attack on Samarra on 4 June, followed by the seizure of Mosul on 10 June, and Tikrit on 11 June. As Iraqi government forces fled south on 13 June, Kurdistan Regional Government force's took control of the oil hub of Kirkuk, part of the disputed territories of Northern Iraq.
