Islamic State

Overview

The Islamic State, also known as ISIS or ISIL, is a Sunni jihadist terrorist organization that seized and governed extensive territory in Iraq and Syria. Its rise during the Syrian civil war and Iraq’s security crisis in 2013–2014 transformed an insurgent network into a territorial power. On June 29, 2014, its leader Abu Bakr al-Baghdadi declared a caliphate and shortened the organization’s name to Islamic State. The declaration sought allegiance from Muslims worldwide but drew rejection from Muslim leaders and scholars. At its height that summer, the organization controlled about one-third of Iraq and between one-quarter and one-third of Syria.

Islamic State rule combined military conquest with executions, abductions, sexual enslavement, religious persecution and the destruction of communities. Its forces murdered captured Iraqi soldiers near Tikrit and carried out a genocidal campaign against the Yazidis in Sinjar. Christians, Kurds, Druze, Shia Muslims and other civilians also faced violence or expulsion. The organization used territorial control to recruit fighters, extract resources and present itself as a state, while its media encouraged or claimed attacks far beyond Iraq and Syria.

Iraqi and Kurdish forces, the Syrian Democratic Forces and other local forces fought Islamic State on the ground. The United States led an international coalition under Operation Inherent Resolve, providing air power, intelligence, training and support. Islamic State lost its territorial rule in Iraq in 2017 and its last territorial enclave in Syria in 2019. Those defeats ended its caliphate as a governing project; surviving operatives, foreign provinces and people held in detention facilities remain continuing security concerns.

Founding and ideology

The movement’s lineage begins with Abu Musab al-Zarqawi, who established Jama’at al-Tawhid wal-Jihad in 1999. His network recruited foreign fighters and developed during the Iraq War. It joined al-Qaeda’s network as al-Qaeda in Iraq, pursuing attacks against American forces, the Iraqi government and Shia Muslims. Zarqawi’s death in 2006 did not end the organization. The Mujahadeen Shura Council subsequently joined other local groups and tribal leaders and declared the Islamic State of Iraq in October 2006. The 2014 caliphate declaration was therefore a later stage in an established movement, not its beginning.

Islamic State adheres to an extremist interpretation of Sunni Islam and pursued political Islam as a governing program. It claimed religious authority over Muslims, rejected existing states and sought to impose its version of Sharia across territory it controlled. Jihad means struggle or effort; the organization invoked armed jihad to justify warfare and used terrorism as a tactic against civilians and security forces. Its doctrines and conduct must be distinguished from Muslims as a whole. Muslim leaders and scholars rejected its claim to a caliphate, while its victims included large numbers of Muslims.

The group also invoked Islamic texts and precedents attributed to Mohammed to defend the capture and sexual enslavement of non-Muslim women. Bill Warner argues that Islamic State drew on both early Meccan and later Medinan material in Islamic tradition and that accounts in the Sira are relevant to interpreting its conduct. The Center for the Study of Political Islam similarly treats the Koran, Sira and Hadith together in its analysis of jihad and political rule. These are attributed interpretations of doctrine; Islamic State’s documented enslavement and abuse remain acts for which the organization bears responsibility.

History

Islamic State of Iraq extended its network into Syria after civil war began there. The Al-Nusra Front, established in January 2012, initially operated as a branch of that Iraqi network. In April 2013, al-Baghdadi announced a union under the name Islamic State in Iraq and al-Sham. Al-Nusra rejected the merger. In June 2013, al-Qaeda leader Ayman al-Zawahiri annulled it and designated Al-Nusra as al-Qaeda’s Syrian branch. The Iraqi leadership defied his authority, producing a hostile split. Islamic State’s subsequent rivalry with al-Qaeda concerned leadership, territory and competing claims to legitimacy within jihadist networks.

During 2013 and 2014, Islamic State exploited Syria’s fragmented war and Iraq’s weakened security forces. It established control around Raqqa and advanced through the Levant and Mesopotamia. In June 2014, its assault on Mosul met an Iraqi army that collapsed before the advance. The fall of Mosul gave the group a major city, military equipment and resources. Competing security forces operated across the nearby Nineveh Plains, home to Assyrian Christian communities. Islamic State also held Fallujah and territory linking Iraqi and Syrian fronts. Al-Baghdadi’s June 29, 2014 declaration followed these gains and made the territorial caliphate central to the organization’s identity.

Its advance continued into 2015. Islamic State captured Palmyra in May and pressed against Syrian government forces, Kurdish defenders and other armed groups. It expelled most Kurds and Christians from Raqqa; before its takeover, they had comprised approximately 20 percent and 1 percent of the city’s population, respectively. Fighting near Kobani in 2014 became a major test of Kurdish resistance. The organization’s operations around Sinjar threatened communities in the Kurdistan Region, while Iraqi forces in 2015 prioritized campaigns in Anbar because they lacked sufficient strength for a decisive Mosul offensive.

Coalition strikes and local offensives gradually reversed these gains. From August 8, 2014, through November 15, 2015, United States forces conducted 6,846 airstrikes against Islamic State targets in Iraq and Syria; other coalition members conducted 1,937. By April 2016, the Pentagon estimated that coalition bombing had killed 25,000 Islamic State fighters, although the organization still fielded an estimated 20,000 to 30,000. Iraqi forces retook Fallujah in 2016, then continued clearing operatives, improvised explosive devices and booby traps. The Battle of Mosul ended Islamic State’s control of that city in 2017. Iraq declared the group’s territorial defeat in December 2017.

In Syria, the Syrian Democratic Forces advanced toward Raqqa from the north and west and began severing its connection to Deir ez-Zor in February 2017. Control of Thawra Dam mattered because it provided irrigation and electricity and offered the only intact crossing on the Islamic State-held stretch of the Euphrates. The Syrian Democratic Forces captured Raqqa in 2017 and continued operations in eastern Syria with American support. Syrian government forces fought Islamic State elsewhere, including along the Euphrates Valley. Turkey’s 2016 Operation Euphrates Shield took territory from Islamic State while seeking to prevent Kurdish forces from consolidating control along its border. Turkey’s 2018 offensive against Kurdish-held Afrin diverted Kurdish fighters from the Euphrates Valley campaign. Islamic State’s last territorial enclave in Syria fell in 2019.

Structure and leadership

Al-Baghdadi led Islamic State through its territorial expansion, caliphate declaration and subsequent losses. Under his leadership, the organization combined central direction with local commanders, security organs, media production and branches it called provinces. Its claim to universal religious authority helped recruit foreign fighters and attract pledges from armed groups outside Iraq and Syria. Coalition forces later recovered computers and hard drives in Mosul containing names that border-control agencies used to identify suspected operatives.

Islamic State’s foreign network expanded into Libya, Egypt, Yemen and regions farther afield. In Libya, its force around Sirte was estimated at 4,000 to 5,000 operatives at its peak, including recruits from other Arab and African countries. Islamic State – Sinai Province increased the scale and ambition of its operations after joining the organization. Boko Haram pledged allegiance in March 2015, becoming part of its West African expansion, although disputes within that relationship followed. Islamic State affiliates also emerged in the Caucasus, Afghanistan and India. Their activity varied by place and time, but the provincial structure allowed the organization to keep claiming attacks after it lost its central territory.

Al-Baghdadi died in a United States raid in 2019. His death removed the organization’s dominant leader and dealt it an operational and symbolic blow, but Islamic State announced a successor and continued claiming attacks. Its Yemen branch released an April 2020 video attacking al-Qaeda’s doctrinal legitimacy, illustrating the continuing rivalry between the two organizations. Later leaders operated without al-Baghdadi’s public prominence. Leadership losses did not dissolve the networks, local cells or foreign provinces established during the caliphate years.

Funding and sponsors

Territorial rule gave Islamic State access to resources unavailable to most clandestine terrorist organizations. Control of cities, roads, oil-producing areas and other infrastructure supported its military operations and administration. Fighting for oil wells near al-Shadadi and for crossings along the Euphrates reflected the strategic value of those assets. The group also used media to recruit and sustain its image as a functioning state. Its financial position weakened as coalition and local forces retook territory, infrastructure and population centers.

Claims about outside sponsors require care. At a June 8 press conference, the Libyan National Army accused a Qatari intelligence general of financing al-Qaeda, Islamic State and the Muslim Brotherhood through a bank transfer. The accusation alone does not establish that the transfer occurred. Islamic State’s documented territorial resources and its relationships with pledged foreign branches provide a firmer account of how it sustained operations during its period of expansion.

Attacks and operations

Islamic State’s violence against prisoners and civilians was central to its rule. It claimed to have executed more than 1,700 Shia Iraqi soldiers at Tikrit; mass graves containing soldiers’ bodies were exhumed there in April 2015. In Sinjar, its campaign against Yazidis included killings, abductions and sexual enslavement. By the end of 2019, investigators had found 81 mass graves containing more than 2,500 Yazidis across Sinjar district and other predominantly Yazidi areas of Nineveh. The Sinjar massacre formed part of the wider Yazidi genocide. The Kurdistan Regional Government maintained a center in Duhok that treated and supported women who survived captivity and documented rape.

Christian communities also faced expulsion and murder. Islamic State’s takeover of Mosul and the Nineveh Plains displaced many Assyrian Christians. Church leaders, including representatives of the Syriac Orthodox Church, met to pray and discuss their communities’ future after its attacks. In Libya, Islamic State operatives beheaded 21 foreign Coptic Christians at Sirte in 2015. Defeating the organization did not by itself secure return to the Nineveh Plains: damaged homes needed rebuilding, and residents remained concerned about renewed violence and rival security forces.

Islamic State attacked military personnel, infrastructure and civilians across several theaters. In February 2016, a Duhok hospital treated nine Peshmerga fighters exposed to chlorine mortar shells fired by its operatives near Sinjar. Its January 16, 2019 suicide bombing against a joint American–Kurdish patrol in Manbij killed 19 people, including four Americans and five Kurds. In Iraq, operatives continued killings, abductions and attacks against security forces in Kirkuk Governorate after the 2017 territorial defeat. They blew up a high-voltage pylon west of Kirkuk on August 18, 2022, as part of a campaign against infrastructure.

Foreign branches and sympathizers extended the threat beyond the former caliphate. The organization carried out attacks in Egypt, including operations by Sinai Province; in November 2022, operatives seized government buildings in Al-Qantara and exchanged fire with Egyptian forces. Its Libyan fighters attacked tanker trucks near Abu Qarin in October 2015 and expanded toward Misrata in 2016 before opposing forces advanced on Sirte. Islamic State media used attacks and territorial losses alike for propaganda. Cooperation between attackers linked to Islamic State and al-Qaeda in the Arabian Peninsula in France arose through local personal ties; it did not establish an alliance between the rival organizations’ leaders.

Designations and international status

Islamic State is a terrorist organization. Its caliphate claim received no general recognition as state authority, and Muslim leaders rejected its attempt to command their allegiance. Governments and international forces organized military, intelligence and financial efforts against it. Baghdad invited a United States-led coalition after Iraq’s army collapsed before the 2014 advance. At their 2016 Riyadh summit, Gulf Cooperation Council and United States leaders committed to intensifying efforts against Islamic State and al-Qaeda while addressing destabilizing activity by the Iranian regime.

Israel regarded Islamic State as a security threat to Israeli citizens, including through potential attacks at its borders and abroad. In 2015, Israeli security analysis called for intelligence and operational measures to prevent such attacks and support the international campaign. The direct threat inside Israel and at its borders remained relatively small, and al-Baghdadi’s death had limited direct security significance for Israel. Israeli relief organization IsraAID also assisted Christian and Yazidi refugees who had fled Islamic State violence to the Kurdistan Region, supported by an American Jewish Committee grant in September 2014.

Current status

Islamic State no longer governs the large territory it held in 2014, but surviving operatives remain active in Iraq, Syria and foreign provinces. Its post-caliphate threat includes clandestine cells at large, detained fighters and the possible recruitment of people growing up in camps holding families and other people associated with the organization. Iraqi forces have continued operations against its leaders and cells. In 2024, several hundred American troops supported Syrian Democratic Forces operations against remnants east of the Euphrates.

Detention poses a persistent challenge. In 2023, the Syrian Democratic Forces oversaw more than 20 detention centers in northeastern Syria holding approximately 9,000 Islamic State fighters; a facility in Hasakah held most of those detained. Affiliates from more than 60 countries were among the detainees. The Al-Hol and Roj camps held more than 70,000 people at their peak and roughly 40,000, mostly women and children, at the time of a later funding assessment. An August 2025 count recorded around 43,250 people classified as noncombatants in eastern Syrian camps, including approximately 25,000 children under twelve. These populations include people with different histories and levels of involvement; detention, repatriation and security decisions concern individuals rather than a single undifferentiated group.

Security around detention sites has itself become a battlefield. An Islamic State attack on Ghweiran prison in Hasakah brought fighting, shelling and fears that prisoners had escaped; nearby residents faced displacement and shortages of basic necessities. On January 18, 2026, the Syrian Democratic Forces and Syrian government announced a tentative ceasefire calling for the transfer of detention facilities and camps to government administration. Fighting near those facilities continued the following day. The episode showed why custody of detainees remains part of the effort to prevent an Islamic State resurgence, even after the defeat of its territorial rule.