TEHRAN -- At least nine people were killed, including six civilians and three gunmen, and 22 others injured in a "terror" attack Saturday morning on the building of the justice department in Iran's southeastern city of Zahedan, capital of Sistan and Baluchestan province, the semi-official Tasnim news agency reported.

The attack has been claimed by Jaish al-Zulm, designated by Iran as a terrorist group, the report said.

Alireza Daliri, Sistan and Baluchestan's deputy police chief, told reporters the "Israeli-linked terrorists" sought to enter the justice department in the guise of ordinary clients at 8:30 am local time (0500 GMT).

The security and law enforcement forces at the department's entrance identified the "terrorists" and engaged in an armed clash with them, Daliri said.

An assailant threw a grenade into the department's premises, killing several clients, including a woman and a one-year-old child, and injuring some others, he added.

The security forces killed three assailants and "currently the terrorist team has been dismantled," Daliri said, adding that the three assailants were wearing suicide vests.

Iran's Islamic Revolution Guards Corps said in a statement that some of those injured in the attack were in critical condition, adding that security forces had the situation under control.

In remarks to Tasnim, Mohammad-Hassan Mohammadi, head of Zahedan University of Medical Sciences, said all the wounded were transferred to nearby hospitals.

Jaish al-Zulm has been involved in deadly attacks against Iranian security forces and civilians in recent years.