General David Petraeus singled out their training of the new Iraqi navy and marines, and support of a major Iraqi-led operation against militias in Basra.
He said: "Our shared experience in Iraq have brought our militaries even closer. As we look together beyond Iraq, your American comrades are heartened that we will continue to serve together in Afghanistan.
"Thanks to each of you for your commitment, your sacrifice and your skill." The UK handed command of coalition forces in Basra to the US last week. The remaining 4,100 British troops in Iraq stop combat operations by May 31 and all but about 400 will be out by July 31..