Death toll from Iran parade attack rises to 24

The semi-official Fars news agency said two gunmen on a motorcycle wearing khakis opened fire on the large crowd of spectators and then attempted to attack the viewing stand for official dignitaries before being shot and wounded by security forces.

Early reports described the assailants as "Takfiri," a term previously used to describe the Islamic State.

Iran's Foreign Minister Mohammad Javad Zarif immediately blamed the attack on regional countries and their "US masters". 

The rare attack targeted Khuzestan, a province bordering Iraq that has a large ethnic Arab community, many of them Sunni, and was a major battleground of the devastating 1980-88 conflict between Iran and Saddam Hussein's Iraq.

Saturday's rally was one of many in cities across Iran held to mark the anniversary of the launch of the war with Iraq.

Attacks by Kurish rebels on military patrols along the border in mainly ethnic Kurdish areas further north are relatively common.

But attacks on regime targets inside major cities are far rarer.

On 7 June, 2017, 17 people were killed and dozens wounded in simultaneous attacks in Tehran on parliament and on the tomb of revolutionary leader Ruhollah Khomeini.

At that point it marked the only attack by the Sunni extremists inside of Shia Iran, which has been deeply involved in the wars in Iraq and Syria, where the militants once held vast territory.

At least 18 people were killed and more than 50 wounded in the 2017 operation that saw gunmen carrying Kalashnikov assault rifles and explosives storm the parliament complex where a legislative session had been in progress, starting an hours-long siege.

The 2017 assault shocked Tehran, which largely has avoided militant attacks in the decades after the tumult surrounding the 1979 Islamic Revolution that ousted the Shah of Iran.

Follow us on Twitter: @The_NewArab