The Harakat Shabaab al-Mujahidin (al-Shabaab)— also known as al-Shabaab, Shabaab, the Youth, Mujahidin al-Shabaab Movement, Mujahideen Youth Movement, Mujahidin Youth Movement, and other names and variations—was the militant wing of the Somalia Council of Islamic Courts that took over most of southern Somalia in the second half of 2006. Although the Somali government and Ethiopian forces routed the group in a two-week war between December 2006 and January 2007, al-Shabaab has continued its violent insurgency in southern and central Somalia. The group has gained control of many parts of southern and central Somalia by using guerrilla warfare and terrorist tactics against the Transitional Federal Government (TFG) of Somalia and its allies, African Union peacekeepers, and nongovernmental aid organizations.

On 29 February 2008, the US Government designated al-Shabaab as a Foreign Terrorist Organization under Section 219 of the Immigration and Nationality Act (as amended) and as a Specially Designated Global Terrorist under Section 1(b) of Executive Order 13224 (as amended). Al-Shabaab’s rank-and-file members come from disparate clans, and the group is continually susceptible to clan politics, internal divisions, and shifting alliances. While most of its fighters are predominantly interested in the nationalistic battle against the TFG and not supportive of global jihad, al-Shabaab’s senior leadership is affiliated with al-Qa‘ida, and certain extremists aligned with al-Shabaab are believed to have trained and fought in Afghanistan. Al-Shabaab has issued statements praising Usama Bin Ladin and linking Somalia to al-Qa‘ida’s global operations. The group has claimed responsibility for many bombings—including various types of suicide attacks—in Mogadishu and in central and northern Somalia, typically targeting Somali government officials and perceived allies of the TFG.
Al-Shabaab’s leaders also have ordered their fighters to attack African Union (AU) peace-keeping troops based in Mogadishu. Al-Shabaab is responsible for the assassination of Somali peace activists, international aid workers, numerous civil society figures, and journalists.