The 2013–2017 war in Iraq was an armed conflict between Iraq and its allies and the Islamic State of Iraq and the Levant which began in 2013 and ended in December 2017. Following December 2013, the insurgency escalated into a full-scale war following the conquest of Ramadi, Fallujah, Mosul, Tikrit and other towns in the major areas of northern Iraq by the Islamic State of Iraq and the Levant. At its height, ISIL held 56,000 square kilometers of Iraqi territory, containing 4.5 million citizens.
This war resulted in the forced resignation of Iraqi Prime Minister Nouri al-Maliki in 2014, as well as a massive airstrike campaign by the United States and at least a dozen other countries, participation of American and Canadian troops in ground combat operations, a $3.5 billion U.S.-led program to rearm the Iraqi Security Forces, a U.S.-led training program that provided training to nearly 200,000 Iraqi soldiers and police, the participation of Iranian troops including armored and air elements, and military and logistical aid provided to Iraq by Russia.