Jihadists from the Islamic State (IS) group have established a stronghold in Somalia’s Puntland region, operating largely undisturbed across a vast mountainous area after setbacks in Iraq and Syria and using it as a base for wider operations in Africa and beyond. Local authorities have launched a major offensive, driving fighters from villages into cave positions amid ongoing clashes and mounting casualties, in a campaign officials say is crucial to restoring stability in Somalia and countering a broader global security threat. A report by Bastien Renouil, Will Swanson and ARTE.