A team of militants linked with Islamic State were paid 600,000 euros (NZ$925,000) to carry out a bombing campaign at 50 locations in Tehran and other big cities in Iran, according to a documentary aired on Iranian state TV.
Officials in predominantly Shi'ite Iran have said in recent weeks that Sunni militants from Islamic State are targeting the country.
Two weeks ago, Iranian intelligence authorities said they had foiled a large-scale terrorist attack, arresting 10 militants, and had seized about 100 kilograms of explosive material that was to be used in car bombs, and suicide and other bomb attacks in busy public places.
The 15-minute documentary, which aired on Monday, featured interviews with two militants after they had been arrested, in which they explained the planned operations.
Footage from a hidden camera which featured in the documentary showed members of the group allegedly purchasing and transporting chemicals and household products that could be used to make explosives.
Near the end of the documentary security agents armed with machine guns and wearing black balaclavas and body armour were shown raiding a house and handcuffing suspects.
The narrator of the documentary said the investigation into the attack was still continuing.
Members of Iran's Revolutionary Guard have fought against Islamic State militants in Iraq as part of their support for the Shi'ite-led government in Baghdad.
Guard members and volunteers are also fighting against Sunni militants in Syria in support of President Bashar al-Assad.
Iranian security forces announced in May that they had arrested a dozen Islamic State fighters in the east and west of the country and also more than 50 sympathisers who were promoting the group's ideology on the internet.