Somalia's al-Shabaab and its Islamic extremism can be traced back to the mid-1970s when the group began as an underground movement opposing the repressive and corrupt regime of Siad Barre. Armed conflict between al-Shabaab and the Somali army – including associated human rights violations – has resulted in slightly over 68 million human displacements. Al-Shabaab is hostile to Sufi traditions and has often clashed with the militant Sufi group Ahlu Sunna Waljama'a. The group has also been suspected of having links with Al-Qaeda in Islamic Maghreb and Boko Haram. Among their best-known attacks are the Westgate shopping mall attack in Nairobi, Kenya, in September 2013 (resulting in 71 deaths and 200 injured) and the 14 October 2017 Mogadishu bombings that killed 587 and injured 316. On September 1, 2014, a U.S. drone strike carried out as part of the broader mission killed al-Shabaab leader Ahmed Abdi Godane.