Iranian authorities said on Sunday they have arrested six people involved in a twin attack on Tehran in which 17 people were killed last week, Reuters reported.
"Six people who were certainly connected to Wednesday’s terrorist attacks in Tehran were identified and arrested," Aliakbar Garousi, head of the justice department in Kordestan province in western Iran was quoted as saying by the Fars news agency.
Iran said its security forces on Saturday killed the mastermind of the attacks, and arrested seven people suspected of helping the militants.
Islamic State has claimed responsibility for the suicide bombings and gun attacks on parliament and the mausoleum of the Islamic Republic's founder, Ayatollah Ruhollah Khomeini, on Wednesday.