CHICAGO - Afghan President Hamid Karzai thanked the United States today for shouldering much of the cost for the decade-old war in Afghanistan, as the NATO alliance readies to hand over primary responsibility to Afghan security forces.

"I'm bringing to you and to the people of the United States the gratitude of the Afghan people for the support that your taxpayers' money has provided us over the past decade, and for the difference that it has made to the well-being of the Afghan people," Karzai said after his meeting with President Obama ahead of the start of the NATO Summit.

The two leaders met in Afghanistan earlier this month where they signed a Strategic Partnership Agreement outlining plans for the U.S.-Afghan relationship from the withdrawal of U.S. troops in 2014 through 2024.

Obama said today that the NATO Summit will be largely devoted to "ratifying" the plan to draw down U.S. and NATO forces and to "painting a vision, post-2014, in which we have ended our combat role."

"The Afghan war as we understand it is over, but our commitment to friendship and partnership with Afghanistan continues," he said. "Both of us recognize that we still have a lot of work to do, and there will be great challenges ahead. The loss of life continues in Afghanistan; there will be hard days ahead. But we're confident that we are on the right track, and what this NATO Summit reflects is that the world is behind the strategy that we've laid out."

Karzai reaffirmed his commitment to the transition process and to the completion of the withdrawal in 2014, "so that Afghanistan is no longer a burden on the shoulder of our friends in the international community, on the shoulders of the United States and our other allies."

Sitting alongside Obama, Karzai told reporters his country is "looking forward to an end to this war" and that they are "fully aware of the task ahead and of what Afghanistan needs to do to reach the objectives that we all have of a stable, peaceful and self-reliant Afghanistan."

NATO Secretary-General Anders Fogh Rasmussen said earlier today that the allied countries remain committed to Afghanistan.

"There will be no rush for the exits," he said.

Rasmussen's comments came two days after newly elected French President Francois Hollande reaffirmed his campaign pledge to withdraw French troops by the end of the year and continue to support Afghanistan in a "different way."