Meanwhile, Qolamreza Masoumi, chief of the country's emergency center, said that the explosion during the military parade has killed 12 people, according to ISNA.
The number of the injured has risen to 81, an unnamed medical official in the Mahabad hospital was quoted by ISNA as saying.
The explosives had been placed in a holdall and went off when people were watching the parade, the report said.
Vahid Jalalzadeh, governor of West Azarbaijan province, told the official IRNA news agency that the killed were mostly women and children, adding "anti-Revolution agents have always carried out such brutal acts to take revenge on the people of Mahabad who are always in the scene."
Ali Nikbakht, director general of political affairs of the West Azarbaijan, said the incident is under investigation.
The police said that they have arrested two suspects, Press TV reported.