An al-Qaida affiliated group in Iraq has claimed responsibility for the assassination of a Sunni parliamentarian who played a leading role in the fight against the group in western Iraq.

In a statement posted early Monday on a militant website, the Islamic State of Iraq, al-Qaida's Iraqi branch, said that its fighters were responsible for last week's killing of Ifan Saadoun al-Issawi, who they called a "dog of the Americans" and the "tail of the Shiites."

Al-Issawi was a founder of a branch of the Sahwa, a group of Sunni fighters who joined forces with the U.S. military to fight al-Qaida at the height of Iraq's insurgency.