He was a Sunni who was working within the Shi'ite government. "We announce to the Islamic nation, to our people and expecially al-Zubayi's tribe, that the soldiers of Iraqi Islam have with Allah's permission struck the so-called vice premier close to his home." From [1] AKI, with thanks to Sr. Soph:

Baghdad, 23 March (AKI) - Al-Qaeda in Iraq has claimed reponsibility for Friday's suicide attack that injured Iraqi deputy premier Salam al-Zubayi. "We announce to the Islamic nation, to our people and expecially al-Zubayi's tribe, that the soldiers of Iraqi Islam have with Allah's permission struck the so-called vice premier close to his home," said a message posted to the Internet, signed by by the 'Iraqi Islamic state', the jihadi formation with which al-Qaeda in Iraq has now merged.

Al-Qaeda received information from its followers that al-Zubayi was seriously injured in the attack - the message said. It concludes with fresh threats directed at all the members Nouri al-Maliki's government, and with a prayer by al-Qaeda's leader in Iraq, Abu Abu Hamza al-Muhajiri, invoking al-Zubayi's death.

A subsequent message will disclose the details of the suicide attack on al-Zubayi's compound, the 'Iraqi Islamic state' said.