http://www.aljazeera.com/news/2017/02/mattis-iran-biggest-state-sponsor-terrorism [login to see] 48014.html
"Iran has been on the State Department’s list of State Sponsors of Terrorism since 1984. Its 2013 Country Reports on Terrorism states that Iran is supporting Hezbollah, Hamas, Palestinian Islamic Jihad, the Popular Front for the Liberation of Palestine-General Command, the Syrian regime (also labeled a State Sponsor of Terrorism), Houthi rebels in Yemen, Shiite militants in Bahrain and Shiite militias in Iraq."