Updated 15:55
At least 25 people have been killed and more than 60 injured after gunmen opened fire during a military parade in Iran.
State media reports that the incident happened in the southwestern city of Ahvaz.
The attackers are said to have been disguised as soldiers.
Authorities said two of the suspected shooters were killed, and two others arrested.
Civilians - including woman and children - who were watching the parade are said to have been among those killed.
At least 60 people were injured and have been taken to local hospitals for treatment.
In this photo provided by Mehr News Agency, civilians try to take shelter in a shooting scene, during a military parade. Picture by: Mehdi Pedramkhoo/AP/Press Association Images
Iran has blamed Arab nationalists for the "terrorist" attack, claiming they were supported by "foreign antagonists".
Local governor Gholam-Reza Shariati told the IRNA news agency: "Terrorists disguised as Islamic Revolution Guards Corps (IRGC) and Basiji (volunteer) forces opened fire to the authority and people from behind the stand during the parade.
“None of the authorities were injured in the incident due to the fast reaction of the security forces."
Iranian President Hassan Rouhani has ordered intelligence services to conduct an 'urgent investigation' into the attack.
The parade was being held as part of nationwide ceremonies to mark the anniversary of the war between Iran and Iraq, which began in September 1980 and lasted for eight years.
