The 37-year-old MP was also part of the Sunni-backed Iraqiyya bloc, which holds some posts in Iraq's fragile national unity government but is also the main opposition to Prime Minister Nouri Maliki.
The main Sunni political bloc, the Iraqi Consensus Front, had pulled out of talks aimed at forming a national-unity government after the shrine bombing, but on Monday it announced that it would rejoin the discussions.