Abdul-Sattar Abu Risha, a young tribal leader who was part of a rare U.S. success story in Iraq that saw Sunnis who were once fighting U.S. military join their cause, met with President Bush just last week during his trip to the region.
The White House said the "unfortunate and outrageous act" was probably carried out by al-Qaida, the Associated Press reported.
The model of enlisting the help of Sunni insurgents against al-Qaida fighters was touted by Gen. David Petraeus, the top U.S. military commander in Iraq, during his testimony before Congress this week, a development that was made possible by cooperation of leaders like Abu Risha.
"A year ago the province was assessed 'lost' politically," Petraeus told a congressional hearing Monday. "Today, it is a model of what happens when local leaders and citizens decide to oppose al-Qaida and reject its Taliban-like ideology."
Abu Risha's cooperation with the Americans brought him praise and support from Iraqis in Ramadi, the provincial capital, but also inspired attempts on his life by members of al-Qaida and criticism from rivals, who saw him as a shameful figure who cooperated with an occupying figure.
White House and U.S. military officials mourned the loss of an important ally in their efforts to stabilize Iraq and eliminate al-Qaida in Iraq, an organization that formed after the U.S. invaded the country in March 2003.
"This is a tragic loss. It's a terrible loss for Anbar province and all of Iraq. It shows how significant his importance was and it shows al-Qaida Iraq remains a very dangerous and barbaric enemy. He was an organizing force that did help organize alliances and did help keep the various tribes together," Petraeus said in a statement, according to the AP.
The news comes as President Bush plans to announce that he is accepting Petraeus' recommendation that the 30,000 troops that came to Iraq in early 2007 as part of a "surge" strategy will come home next summer. This would leave 135,000 U.S. soldiers in Iraq three months before the 2008 presidential election.
Congressional Democrats announced that they are drafting legislation that would limit the U.S. military's role in the conflict to training Iraqi police and military units, fighting terrorists and protecting U.S. assets there, the AP reported.
While the Democrats took control of Congress in November 2006 largely because voters were unhappy with the war, the party so far has been unable to garner the support from Republicans to force President Bush to end American involvement in Iraq.