Iranian security forces said they had arrested a gunman who carried out the attack at the Shah Cheragh shrine in the city of Shiraz Daesh has claimed previous violence in Iran, including deadly twin attacks in 2017 that targeted parliament and the tomb of the Islamic Republic’s founder, Ayatollah Ruhollah Khomeini DUBAI: Iran’s supreme Leader vowed on Thursday to retaliate against those threatening the country’s security after the massacre of Shiite pilgrims, an assault claimed by Daesh which threatens to inflame tensions amid widespread anti-government protests. Ayatollah Ali Khamenei said the assailants “will surely be punished” and called on Iranians to unite. “We all have a duty to deal with the enemy and its traitorous or ignorant agents,” he said in a statement read on state television a day after the attack killed 15 people. Khamenei’s call for unity appeared to be directed at mostly government loyalists and not protesters whose nearly six-week-old movement is seen by authorities as a threat to national security. Iran’s clerical rulers have faced nationwide demonstrations since the death in police custody of Mahsa Amini, a 22-year-old Kurdish woman, on Sept. 16. Iranians have called for the death of Khamenei and an end to the Islamic Republic during the protests, which have become one of the boldest challenges to the clerical leadership since the 1979 revolution, drawing many Iranians on to the streets. Security forces said they had arrested a gunman who carried out the attack at Shah Cheragh shrine in the city of Shiraz. A senior official said the suspected attacker was in critical condition after being shot by police. “We have not been able to interrogate him yet,” said deputy provincial governor Easmail Mohebipour, quoted by the semi-official Tasnim news agency. CCTV footage broadcast on state TV on Thursday showed the attacker entering the shrine after hiding an assault rifle in a bag and shooting as worshipers tried to flee and hide in corridors. Daesh, which once posed a security threat across the Middle East, has claimed previous violence in Iran, including deadly twin attacks in 2017 that targeted parliament and the tomb of the Islamic Republic’s founder, Ayatollah Ruhollah Khomeini. Since the peak of its power, when it ruled millions of people in the Middle East and struck fear across the world with deadly bombings and shootings, Daesh has slipped back into the shadows. Wednesday’s killing of Shiite pilgrims came on the same day that Iranian security forces clashed with increasingly strident protesters marking 40 days since Amini’s death. Iranian leaders may have hoped that the shrine attack would draw attention away from the unrest but there is no sign that is happening. The official news agency IRNA said protesters angry over the “suspect” death of a demonstrator broke windows of banks, a tax office and other public buildings in the northwestern city of Mahabad. The Kurdish human rights group Hengaw said security forces killed at least five people during protests on Thursday in the northwest of the country, where many Kurds live. Three were killed in the city of Mahabad and another two in Baneh. Reuters could not independently verify the reports. Iranian human rights groups said there were unconfirmed reports that some members of Amini’s family are under house arrest. The authorities, who have accused the United States and other Western countries of fomenting what they call “riots,” have yet to declare a death toll, but state media have said about 30 members of the security forces have been killed. Tasnim news agency said a member of the elite Revolutionary Guards had been killed in Tehran province by “rioters” using a hand grenade. The activist news agency HRANA said in a posting that at least 252 protesters had been killed in the unrest, including 36 minors. It said more than 13,800 people had been arrested in protests in 122 cities and towns and some 109 universities.