EXPLAINER-Does Islamic State still pose a threat?

U.S.-backed fighters say they have captured Islamic State's last shred of ground in eastern Syria - but while its era of territorial rule may be over for now, there is near universal agreement that IS remains a threat. Islamic State's possession of land in Iraq and Syria set it apart from other like-minded groups such as al Qaeda and became central to its mission when it declared a caliphate in 2014, claiming sovereignty over all Muslim lands and peoples.