Sheikh Abdul Sattar Abu Risha was a key Sunni Arab ally of the US and Iraqi governments in Iraq's western Anbar province.
Abu Risha was praised for his help in expelling al-Qaeda fighters
The 37-year-old leader of the Al Bu Risha tribe was killed in a bomb attack near his home in the provincial capital, Ramadi, on Thursday.
He was reportedly a top target for assassination by al-Qaeda in Iraq, whom he is widely credited with having defeated in much of western Iraq.
Abu Risha, who also ran a construction and import-export business with offices in Jordan and Dubai, was among a group of tribal leaders who met President George W Bush during his visit to Iraq last week.
Abu Risha was part of a group of young tribal sheikhs whose power grew after more senior leaders fled Anbar or were killed in the insurgency that gripped the province.
Some 24 tribes and organisations joined the Anbar Awakening
In September 2006, angered by the killings of both his father and two brothers by al-Qaeda in Iraq, Abu Risha approached the US military about forming an alliance to fight the Sunni extremist group.
The US agreed to provide funding and soon began to train members of the sheikh's tribe and placed a M1 tank outside his compound to provide protection.
According to the deputy US commander in Iraq, Gen Raymond Odierno, the "handshake agreement" was based on the tribes agreeing to three conditions:
- halting action against US-led coalition and Iraqi forces
- pledging to fight al-Qaeda in Iraq
- attempting to draw the tribal militias into the Iraqi security forces, especially the police
Other tribal leaders began to join the so-called Anbar Salvation Council, or Anbar Awakening, after seeing it was possible to secure their own communities, and soon the council had a force of 2,100 men.
The development led to a sharp reduction of violence in the province and forced many al-Qaeda fighters to flee to other provinces.
By March, Abu Risha's militia and the US military claimed they had essentially evicted al-Qaeda from Ramadi, the provincial capital.
'Spontaneous popular uprising'
On Tuesday, a large rally was held in Ramadi to mark the first anniversary of the Anbar "awakening".
Afterwards, Abu Risha told the Dubai-based Arabic TV news channel, al-Arabiya, that there had been a "spontaneous popular uprising" against al-Qaeda because the group had killed the province's people.
"We did not support the US forces or anyone else. We fought on behalf of our people and defeated al-Qaeda," he said.
Abu Risha said al-Qaeda had come "from across the border" to destroy Islam.
"We came to save Iraq from deaths, terrorism, and ruin," he added.
"We will continue to defend Iraq and we will continue to raise the flag of Allahu Akbar (God is the greatest), and we will enter Baghdad. We are not interested in the post of minister, prime minister, or president of the republic."