Dubai: Up to nine military men were killed when unknown militants opened fire during a military parade in southwestern Iran on Saturday, the semi-official ISNA news agency quoted an official as saying.

State television said the assault, which also wounded 20 people, targeted a stand where Iranian officials were gathered to watch an annual event marking the start of the country’s 1980-88 war with Iraq.

Four militants carried out the attack and two of them were killed, according to ISNA. There has been no claim of responsibility for the attack in the city of Ahvaz.

Iran was holding similar parades in several cities including the capital Tehran and the port of Bandar Abbas on the Gulf.

‘Shooting began by several gunmen from behind the stand during the parade. There are several killed and injured,’ a correspondent told state television.

The semi-official news agency Mehr said further shooting broke out as some of the attackers who managed to escape were being chased.

State television blamed ‘takfiri elements’, a reference to Sunni Muslim militants, for the attack. Ahvaz is in the centre of Khuzestan province, where there have been sporadic protests by the Arab minority in mainly Shi’ite Iran.

Iran will respond ‘swiftly and decisively’ to an attack on a military parade in southwestern Iran, Foreign Minister Mohammad Javad Zarif said, holding agents of a foreign regime responsible.

‘Terrorists recruited, trained, armed & paid by a foreign regime have attacked Ahvaz,’ Zarif tweeted. ‘Iran will respond swiftly and decisively in defense of Iranian lives.’

ISNA said an unnamed spokesman for the elite Revolutionary Guards security force blamed Arab nationalists backed by Saudi Arabia for the attack.

Tensions between traditional rivals Iran and Saudi Arabia have surged in recent years, with the two countries supporting opposite sides in wars in Syria and Yemen and rival political parties in Iraq and Lebanon.

Attacks on the military are rare in Iran.

Last year, in the first deadly attack claimed by Islamic State in Tehran, 18 people were killed at the parliament and mausoleum of Ayatollah Ruhollah Khomeini, the founder and first leader of the Islamic Republic.