of them, leaving them along a road to be found by passersby. At the end of 2018, ISS claimed to have carried out 66 attacks, more than in 2016 and 2017 combined. The group also grew more sophisticated and further expanded its presence throughout Somalia. It had begun to collect taxes (essentially protection money) on businesses in Bosaso by August 2018, greatly increasing its revenue. At some point in 2018, ISS managed to convince a significant number of al-Shabaab militants to defect, resulting in the formation of an Islamic State cell in Beledweyne. As result of its increasing activity in central and southern Somalia, the rivalry between ISS and al-Shabaab reignited in full, with several clashes occurring between the groups. In October 2018, al-Shabaab probably executed ISS deputy, Mahad Maalin in Mogadishu, while Islamic State forces ambushed an al-Shabaab group near B'ir Mirali southwest of Qandala, reportedly killing 14 rival militants. The growing violence between the two jihadist rebel factions resulted in al-Shabaab central command releasing a speech as well as an 18-page treatise on 20 December 2018. In these works, the Islamic State was sharply rebuked as corrupt, apostate, and seditionist force, while al-Shabaab authorized its loyalists to destroy ISS elements as "disease in the Jihad". This amounted to an official declaration of war. In the next months, the two factions greatly increased their attacks against each other: They clashed near El Adde in December 2018, and at numerous locations in Puntland between January and March 2019. ISS reportedly suffered one major setback during these clashes when it lost one of its main bases in the Dasaan area to al-Shabaab. Regardless, neither organizations appears to have suffered to a tangible degree from this inter-rebel fighting, and both have continued to strike government targets. The United States Air Force carried out an airstrike against ISS on 14 April 2019, killing its deputy Abdihakim Mohamed Ibrahim at Xiriiro, Bari region. On 12 July 2019, ISS militants clashed with security forces near the Safa hotel in Puntland's capital, Bosaso, the same day as an al-Shabaab attack on a hotel in Kismayo. The United States Air Force bombed an ISS base in the Golis Mountains on 8 May 2019, reportedly killing 13 militants. On 27 October 2019, IS Caliph Abu Bakr al-Baghdadi was killed in the Barisha raid, whereupon the organisation's central command elected Abu Ibrahim al-Hashimi al-Qurashi as new leader. On 4