At least 15 people were killed including women and children in an attack on a Shia Muslim shrine in the Iranian city of Shiraz on Wednesday, state news agency, IRNA reported.
As per reports, the attackers shot at pilgrims and staff of the shrine from a car.
Police has arrested two of the three terrorists and were looking for the third accused.
Some reports suggest that the attackers were takfiri terrorists, an armed Sunni Islamist groups, however, Iran's top security body, said they were not Iranian nationals.
Meanwhile, the Islamic State group has claimed responsibility for the attack on Wednesday.
“An IS 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.
The attack took place on the same day when the Iranian security forces allegedly opened fire at mourners who gathered in Saqez marking 40 days since the death of Mahsa Amini.