At least 10 people have been killed and more than 20 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.
A woman and child are reported to be among the injured people, while officials said a soldier was among those killed.
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."
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.