Iran’s Revolutionary Guard was left in shock over a surprise attack that took place on Saturday against a military parade in the southwestern Ahwaz region, killing and wounding dozens of army men. The Ahvaz National Resistance claimed responsibility for the attack, a group’s spokesman told Reuters. In contrast, ISIS announced responsibility for the attack on its official Amaq news agency. But the Revolutionary Guard downplayed ISIS’s claims and directed accusations towards anti-regime Ahvazi minorities. Although eyewitnesses reported 40 people being killed, Iran’s head of the parliamentary defense committee Mujtaba Zul Nuri claimed the death of 29 people and injury of 57. Gunmen opened fire approximately 15 minutes after the military parade began, eyewitnesses reported. Three attackers were killed at the scene and the fourth died later of his injuries, added armed forces spokesman Brigadier General Abolfazl Shekarchi. In early hours of the attack, Revolutionary Guard agencies circulated footage showing panic spreading among soldiers. Tehran accused regional states and the United States of standing behind the attack and vowed to “respond.” Supreme leader Ali Khamenei demanded that attackers be tracked down a few moments after Iranian President Hassan Rouhani issued similar orders to security services. It is worth noting that the attack took place simultaneously with Rouhani delivering a speech in Tehran. “The response of the Islamic Republic of Iran to the smallest threat will be crushing”, Rouhani later said in a statement on his official website. Iranian Foreign Minister Mohammad Javad Zarif posted a tweet with four pictures from the government-affiliated ISNA news agency showing panic among women and children. Zarif said the attack was carried out by "terrorists recruited, trained, armed and paid by a foreign regime". "Iran holds regional terror sponsors and their US masters accountable for such attacks," he wrote on Twitter. On Friday, the Revolutionary Guard and the Iranian army held a joint aerial military drill in the Gulf, where the US keeps a fleet to protect oil shipping routes, reported Reuters. “Targeting of the Revolutionary Guard during a military parade in Ahwaz, by Ahvaz National Resistance forces, comes within the framework of self-defense and against a worldwide recognized terrorist military militia,” tweeted head of the Arab Struggle Movement for the Liberation of Ahvaz politburo Habib Jabir.