Islamic State
Islamic StateReuters

The Islamic State (ISIS) group on Wednesday claimed responsibility for an attack on a Shiite Muslim shrine in southern Iran that state media said killed more than a dozen people.

An ISIS fighter opened fire on worshippers at the Shah Cheragh shrine in the city of Shiraz, "killing at least 20 Shiites and wounded dozens of others", the group said in a statement via Telegram channels and quoted by AFP.

Footage posted online showed the attacker just before entering the scene and starting the shooting spree.

State television reported that at least 13 people were killed in the attack. 40 others were wounded when "terrorists attacked the Shah Cheragh mausoleum in Shiraz", the state broadcaster said, according to AFP.

At least one woman and two children were among those killed, Fars news agency said.

Iran's presidency in a statement promised a "severe response" and condemned "the enemies of Iran" who attempt to "divide the united ranks of the nation... through violence and terror".

Local media reported three assailants carried out the attack and that two had been detained, with Fars news agency saying "the terrorists are not Iranian".

The Shah Cheragh mausoleum is home to the tomb of Ahmad, brother of Imam Reza, the eighth Shiite imam, and is considered the holiest site in southern Iran.