The United States carried out a military operation that killed a senior ISIS leader in Syria on Monday, US Central Command (CENTCOM) said on Tuesday, the latest blow to a group that once struck fear across the Middle East. Khalid 'Aydd Ahmad al-Jabouri was responsible for planning ISIS attacks in Europe and developed the leadership structure for the group, the statement said. ISIS controlled swathes of Iraq and Syria at the peak of its power in 2014 before being beaten back in both countries. The group is estimated to have 5,000 to 7,000 members and supporters spread between Syria and Iraq, roughly half of them fighters, a UN report said in February. No civilians were killed or injured in this strike, CENTCOM said, adding that the group "continues to represent a threat to the region and beyond". "Though degraded, the group remains able to conduct operations within the region with a desire to strike beyond the Middle East," the statement said. It added that al-Jabouri's death would "temporarily disrupt the group's ability to plot external attacks". The UN report said the threat posed by ISIS and its affiliates to international peace and security was high in the second half of 2022 and had increased in and around conflict zones where it has a presence. Late last year, ISIS announced it had appointed a previously unknown figure - Abu al-Hussein al-Husseini al-Quraishi - as its leader after the previous leader was killed in southern Syria.