Mohammad Hadi Imanieh said that the attacker had apparently intended to target people holding congregational prayer at the basement of the holy shrine.
He added, the assailant failed to enter the basement because its door was closed and he began shooting at people at the entrance of the shrine.
Imanieh said that the attacker had also got injuries and is now in police custody.
The deputy Fars governor-general for political and security affairs told DayliNews.ir that 15 people had been killed in the terrorist attack and 27 others wounded.
Esmail Mohebbipur said that some of the wounded people are in critical condition.
Follow us on Twitter @DayliNews_ir