America's top military commander in Iraq and the US ambassador in Baghdad are testifying in Congress about the results achieved so far by the six-month-old US troop expansion. Here are some key quotes:
GEN DAVID PETRAEUS, US COMMANDER IN IRAQ
The military objectives of the surge are in large measure
I believe we will be able to reduce our forces to pre-surge level by next summer without jeopardising the security gains.
Like Ambassador Crocker, I believe Iraq's problems will require a long-term effort. There are no easy answers or quick solutions. And although we both believe this effort can succeed, it will take time.
Our assessments underscore, in fact, the importance of recognising that a premature draw-down of our forces would likely have devastating consequences.
It is increasingly apparent to both coalition and Iraqi leaders that Iran, through the use of the Quds force, seeks to turn the Iraqi special groups into a Hezbollah-like force to serve its interests and fight a proxy war against the Iraqi state and coalition forces in Iraq.
The tribal rejection of al-Qaeda that started in al-Anbar province and helped produce such significant change there, has now spread to a number of other locations.
RYAN CROCKER, US AMBASSADOR TO IRAQ
I intend to demonstrate that it is possible for the United States to see its goals realised in Iraq, and that Iraqis are capable of tackling and addressing the problems confronting them today.
A secure, stable, democratic Iraq, at peace with its neighbours, is attainable.
The trajectory of political, economic and diplomatic developments in Iraq is upwards, although the slope of that line is not steep.
I am certain that abandoning or drastically curtailing our efforts will bring failure.
An Iraq that falls into chaos or civil war will mean massive human suffering well beyond what has already occurred within Iraq's borders.
I do believe that Iraq's leaders have the will to tackle the country's pressing problems - although it will take longer than we originally anticipated because of the environment and the gravity of the issues before them.
I believe they approach the task with a deep sense of commitment and patriotism.
TOM LANTOS, HOUSE FOREIGN AFFAIRS COMMITTEE CHAIRMAN
We and the American people already know that the situation in Iraq is grim, and the growing majority of this Congress and of the American people want our troops out.
The current escalation in our military presence in Iraq may have produced some tactical successes. But strategically, the escalation has failed.
It was intended to buy time for [Iraqi] Prime Minister [Nouri] Maliki and the other Iraqi political leaders to find ways to move toward the one thing that may end this terrible civil conflict, and that, of course, is a political settlement. As best we can see, that time has been utterly squandered.
IKE SKELTON, HOUSE ARMED SERVICES COMMITTEE CHAIRMAN
While our troops were holding back the opposing team to let them make a touchdown, the Iraqis haven't even picked up the ball.
The witnesses must tell us why we should continue sending our young men and women to fight and die if the Iraqis won't make the tough sacrifices leading to reconciliation.
What is the likelihood that things will change dramatically and there will be political progress in the near term? Are we merely beating a dead horse?