ISIS-linked attacks abroad

Faced with setbacks in its core territories in 2015, ISIS began focusing its efforts on using international networks of militants to carry out attacks around the world. On November 12 two suicide bombers struck a Shiʿi neighborhood in Beirut, killing more than 40 people in retaliation for the Shiʿi militant group Hezbollah’s intervention against ISIS in Syria. A day later eight ISIS-affiliated gunmen launched a series of coordinated gun and bomb attacks in Paris, killing at least 130 people at several sites around the city. ISIS spokesmen claimed the attacks as revenge for France’s participation in the international military campaign against ISIS.

Over the months that followed, a series of ISIS-linked attacks unfolded around the globe. In some cases, such as the bombing in March 2016 that killed 32 people at Brussels Airport, investigators were able to confirm that there had been operational coordination between the perpetrators and ISIS commanders. In other instances, though, such as two shooting rampages in the U.S.—in San Bernardino, California, in November 2015 and in Orlando, Florida, in June 2016—the perpetrators declared allegiance to ISIS but appeared not to have been in contact with its command structure. Such attacks, often called “homegrown” or “lone-wolf” attacks in the media, had been explicitly encouraged by ISIS in its propaganda as a way to spread violence beyond the reach of its networks of militants.

ISIS affiliates in Libya

Outside of Iraq and Syria, ISIS-affiliated groups appeared to be most strongly established in North Africa. In Libya—fragmented by factional conflict after the deposal of Muammar al-Qaddafi in 2011—ISIS established control of more than 100 miles (160 km) of coastline. The group claimed responsibility for a series of attacks and released videos in early 2014 showing purported ISIS fighters carrying out mass executions of Christian hostages from Egypt and Ethiopia. By mid-2015 ISIS had captured Sirte, a strategic city linking the eastern and western halves of Libya. Sirte was recaptured by Libyan forces in December 2016.

Islamic State–Khorasan Province

In January 2015 disaffected members of the TTP pledged allegiance to ISIS. They took on the name Islamic State–Khorasan Province (ISKP; also called ISIS-K), a moniker that referred in irredentist fashion to the historical region of Khorāsān in early Islamic history, and initially received guidance and support from ISIS during the latter’s peak. Some factions of the TTP, the Afghan Taliban, and Lashkar-e-Taiba, which accused those groups of being more nationalist in outlook than universal, joined ISKP.

ISKP reached its peak in 2016, when its force numbered more than 3,000 fighters and enjoyed its greatest level of centralized command. Its leader, Hafiz Saeed Khan, was killed in August of that year; subsequent leaders were quickly killed or arrested. In 2017 the United States dropped its most powerful conventional weapon—the GBU-43/B MOAB bomb—to destroy a complex of caves and tunnels used by ISKP as its base. The group continued to diminish as it faced assault from U.S. forces, the Afghan government, and the Afghan Taliban. Nonetheless, instability left Afghanistan vulnerable to ISKP, and in August 2021 the group killed about 170 Afghans and 13 Americans outside the airport in Kabul as U.S. troops were evacuating refugees from the country.

Islamic State–West Africa Province (Boko Haram)

Like ISKP, the Nigerian affiliate pledged allegiance to ISIS in 2015. Founded in 2002, the movement in Nigeria actually long predated ISIS and was most widely known by the name Boko Haram. It has a more localized orientation, concentrating on targets in Nigeria, rather than the dedication to transnational jihad that is characteristic of other ISIS affiliates. Its rhetoric nonetheless corresponds to that of ISIS, rejecting what it characterizes as the Westernization of Nigeria and blaming Western influences for a culture of corruption in the country. A cycle of escalating violence began in 2009 when the group responded to an alleged pattern of excessive use of force by the police by attacking police posts and other government installations. By late 2010 it was attacking both Muslim and Christian civilian targets, most notoriously attacking schools, but it gained a reputation for targeting Christians in particular after attacking two churches on Christmas Eve that year. In August 2011 a suicide bomber associated with Boko Haram crashed a car into a United Nations building in Abuja, marking its first major attack on an international target, albeit located within Nigeria. In 2013, after Boko Haram rejected a proposal for amnesty by Nigerian Pres. Goodluck Jonathan if they disarmed, Jonathan declared the group a terrorist organization and launched a military offensive. The group declared allegiance to ISIS following another offensive in early 2015, which effectively uprooted Boko Haram in much of the area it had held.