What Happened Four gunmen opened fire on a military parade and celebration in Ahvaz, capital of Iran's Khuzestan province, on Sept. 22. The attack killed at least 25 people — including 12 members of Iran's Islamic Revolutionary Guard Corps — and injured more than 70 others. Though it is still unclear who committed the attack, Iranian officials were quick to point the finger at local separatist groups and at international rivals such as the United States and Saudi Arabia. Why It Matters The Islamic State claimed responsibility for the shooting through its news agency, Amaq, and published a video that it said showed the assailants. But the video made no mention of the target, and the men in it did not profess allegiance to the Islamic State or to the group's leader, Abu Bakr al-Baghdadi.