Military of the Islamic State

The Military of the Islamic State is the fighting force of the Islamic State (IS). The total force size at its peak was estimated from tens of thousands to over 200,000. IS's armed forces grew quickly during its territorial expansion in 2014. The IS military, including groups incorporated into it in 2014, openly operates and controls territory in multiple cities in Libya and Nigeria. In October 2016, it conquered the city of Qandala in Puntland, Somalia. It conquered much of eastern Syria and western Iraq in 2014, territory it lost finally only in 2019. It also has had border clashes with and made incursions into Lebanon, Iran, and Jordan. IS-linked groups operate in Algeria, Pakistan, the Philippines, and in West Africa (Cameroon, Niger, and Chad). In January 2015, IS was also confirmed to have a military presence in Afghanistan and in Yemen.

The Islamic State's military is based on light infantry mobile units using vehicles such as gun-equipped pick-up trucks (technicals), motorbikes and buses for fast advances. They have also used artillery, tanks and armored vehicles, much of which they captured from the Iraqi and Syrian Armies. IS has a long history of using truck and car bombs, suicide bombers, and improvised explosive devices. They have also deployed chemical weapons in Iraq and Syria.

According to the Institute for the Study of War, IS's 2013 annual report reveals a metrics-driven military command, which is "a strong indication of a unified, coherent leadership structure that commands from the top down". Middle East Forum's Aymenn Jawad Al-Tamimi said, "They are highly skilled in urban guerrilla warfare while the new Iraqi Army simply lacks tactical competence."

IS's Military Council is made up of numerous former military officers from the Saddam Hussein era. Commanders have included Haji Bakr, a colonel; Abu Abdulrahman al-Bilawi, a captain; and Abu Ayman al-Iraqi, a lieutenant colonel, who all graduated from the same Iraqi military academy. Abu Muslim al-Turkmani, al-Baghdadi's former deputy, was a Directorate of General Military Intelligence lieutenant colonel. All these men spent time detained in Camp Bucca during the American occupation of Iraq Abu Omar al-Shishani, who was a sergeant in the Georgian Army before leading an IS unit in Syria, also became a prominent commander.

IS's fighters are reportedly organised into seven branches: infantry, snipers, air defence, special forces, artillery forces, the "army of adversity", and the Caliphate Army. This force structure is largely replicated in each of its designated provinces, with the most skilled fighters and military strategists in each area serving in the special forces unit, which is not allowed to redeploy to other provinces. Parallel to this structure is the Caliphate Army, which is directed by IS's central command rather than its provincial leadership. Made up overwhelmingly of foreign fighters, it is deployed to assist in battles across the Islamic State. There is also an all-female Al-Khansaa Brigade tasked with enforcing religious laws. According to battle reports, IS often operates in small mobile fighting units.

The Islamic State also operates outside areas it largely controls using a clandestine cell system. An IS-linked senior militant commander in Sinai told Reuters; "They [IS] teach us how to carry out operations. We communicate through the internet, ... they teach us how to create secret cells, consisting of five people. Only one person has contact with other cells. They are teaching us how to attack security forces, the element of surprise. They told us to plant bombs then wait 12 hours so that the man planting the device has enough time to escape from the town he is in."

The military of IS is organized as a mixture of an irregular insurgent force and a conventional army. In its Syrian and Iraqi territory, the Islamic State organized professional units for specialised tasks, with the "Tank Battalion", the "Artillery Battalion", and the "Platoons of Special Tasks" being among the most important. The first one employed heavy armoured fighting vehicles, the second heavy artillery, while the last one was used as a rapid intervention force. The three regularly worked in tandem for breakthrough and important defense operations, made possible by a well-organised logistics system that kept operating even under regular bombardments by anti-IS forces.

In contrast to these elite forces, most of IS' troops were local militias with few heavy weapons, usually deployed as territorial defense units. Less trained or less valuable troops were sometimes involved with offensive operations, although their tactics were less sophisticated. The Islamic State stood in sharp contrast to some other jihadist organizations such as the Caucasus Emirate which generally attempted to minimize their own casualties, and became notorious for its willingness to sacrifice many of its fighters. This is especially true in regard to IS's callous use of new recruits. Islamic State military training had a reputation for its strong focus on indoctrination, often to the detriment of more pertinent lessons. The organization's high command used inexperienced recruits for swarming and human wave tactics, often resulting in extremely high casualties. One high-ranking IS commander known for this approach was Abu Omar al-Shishani, who successfully employed swarming tactics during the Siege of Menagh Air Base and Battle of Tabqa Airbase. According to his reasoning, the enemy would eventually be overwhelmed or run out of ammunition regardless of the casualties among IS fighters. Regional expert Joanna Paraszczuk sarcastically remarked that al-Shishani's tactics were based on the belief that "everyone want[s] to be a Shahid" (martyr), although not all Islamic State commanders showed such a readiness to sacrifice troops.