section_path: History/2013–2017: Regrouping
section_name: 2013–2017: Regrouping
paragraph_text: 2013–2017: Regrouping
  
  Following its territorial losses, al-Shabaab reverted to the tactics of asymmetric warfare, launching guerrilla attacks on AMISOM and government positions and territories. Southern commander Aweys had announced this new strategy in a media interview shortly after the withdrawal from Mogadishu in August 2011. Al-Shabaab increasingly avoided direct military combat and large battles, in favour of "dictat the conflict's pace by undertaking smaller ambushes at locations of its own choosing". The group undertook high-profile attacks outside Somalia such as the Westgate shopping mall attack by four militants left 67 dead - the deadliest attack in Kenya since the 1998 US embassy bombings in Nairobi. That death-toll was exceeded two years later in the Garissa University College attack in which 148 people were killed in an attack targeting Christian students. Furthermore, two sophisticated attempts to target airliners were observed in 2016. In February a device in a laptop bag that had passed screening was detonated mid-flight, killing only the bomber, and in March another laptop bomb exploded during screening. Reacting to apparent advances in the group's bomb-making capabilities, the UN Security Council later prohibited the transfer of bomb components to Somalia. The group has also developed a strategy of maintaining a "semi-territorial presence" in key regions and parts of key cities: while it no longer had exclusive and military authority over substantial territory, it retained a sporadic presence, and therefore significant influence, in many places.
  
  Nonetheless, by 2016, al-Shabaab was viewed as significantly weakened by the military campaign against it, with earlier losses compounded in 2014–15 by Operation Indian Ocean, a joint endeavour by AMISOM, the Somali government, and the United States. The Somali government claimed in October 2014 that over 700 al-Shabaab militants had surrendered since September, when it had extended an amnesty offer to them. Reports of further senior defections continued into 2015. Moreover, an American drone strike killed Godane on September 1, 2014; he was succeeded as al-Shabaab leader by Ahmad Diri, who took office the same week. Other senior members were killed in armed clashes or by American drone strikes in 2014 and 2015. According to some reports, since Godane's death, the group has placed less weight on global jihad than on local grievances.