Members of Iran's Revolutionary Guards
Members of Iran's Revolutionary GuardsReuters

Iran’s Revolutionary Guards claimed on Tuesday they had killed the “mastermind” behind an attack on a military parade in the Iranian city of Ahvaz last month which left 25 people dead, Reuters reports.

The Guards said in a statement published on state media their forces had killed a man named Abu Zaha and four other jihadists in Diyala province in Iraq. One news website run by Iran’s state television said Abu Zaha was a member of the Islamic State (ISIS) jihadist group.

The attack was claimed by the Islamic State (ISIS), but it was also claimed by a movement called the "Ahwaz National Resistance", an Arab separatist group.

ISIS had posted a video of three men who allegedly carried out the attack and later threatened to carry out new attacks in Iran, saying the Islamic Republic is "flimsier than a spider's web, and with God's help, what comes will be worse and more bitter".

On October 1, Iran said it had killed several Islamic State leaders in eastern Syria in a missile strike and destroyed their supplies and infrastructure.

News of the killing of the alleged “mastermind” of the attack comes two days after Iranian authorities detained a member of the military in connection with the attack.

Iranian President Hassan Rouhani has accused the US and the Gulf states of responsibility for the Ahvaz attack.

"The group behind the attack was financed and received military backing from the Gulf states - and the United States supplies the resources to the Gulf states to carry out these crimes," Rouhani said, adding that Iran would "respond to these crimes within the framework of the law and international interests."

Similarly, Iranian Foreign Minister Mohammad Javad Zarif blamed the attack on “regional terror sponsors and their US masters”.

US Secretary of State Mike Pompeo was subsequently asked about Zarif’s comments in an interview and replied, “When you have a security incident at home, blaming others is an enormous mistake. And the loss of innocent life is tragic, and I wish Zarif would focus on keeping his own people secure rather than causing insecurity all around the world.”