Shiraz: An armed attack on the Shah Cheragh shrine in the Iran city of Shiraz left 15 people dead on Wednesday and injured 40.

The gun attack occurred on worshipers in a Shia pilgrimage site in Shiraz city, leaving 40 people wounded, Al Arabiya reported citing local Iranian media.

ISIL (ISIS) took responsibility for the brutal attack in a statement on their telegram channel. The attackers targeted the Shah Cheragh shrine in Shiraz at around 5:45 p.m. (local time). ISIL (ISIS) claimed responsibility for the attack in a statement on their telegram channel.

Iranian President, Ebrahim Raisi vowed to respond to the attack and stated that it will not go unanswered.

"This crime will definitely not go unanswered, and the security and law enforcement forces will teach a lesson to those who designed and carried out the attack," Al Arabiya reported quoting Raisi as saying.

According to local media, the attack was initiated by three gunmen, out of which two have been caught and one is still on the run. However, the police chief as well as the chief justice of Fars province refuted any such claims and said there was only one attacker, adding that he was being interrogated.

The Wednesday attack comes as the unrest in Iran continues unabated as anti-government protests sparked by the death of 22-year-old Mahsa Amini in police custody have only surged in Iran since September 16.

Over 200 protesters have been killed and thousands have been arrested, according to rights groups, reported Al Arabiya.

After the death of Amini, there have been widespread rallies and strikes throughout the country's Kurdish region.

Initial public expressions of anger at Amini's death and Iran's decades-old mandatory public headscarf policy for women quickly evolved into Iranian protesters calling for more freedoms and the death of Iran's Islamist rulers.