BBC — US President Barack Obama has pledged to "finish the job" and end the Afghan war, addressing the US public live from a military base in Afghanistan.
Speaking on the anniversary of Osama bin Laden's death, he thanked US troops and hailed plans to combat operations.
Obama arrived in Afghanistan on a surprise visit to sign an agreement on future Afghan-US ties with President Hamid Karzai, ahead of a Nato summit.
At the signing, Obama said it was "a historic moment" for both nations.
Obama's address comes as correspondents say public patience with the war in Afghanistan is wearing thin.
In the prime-time speech, the US president said that at the upcoming Nato summit, to be held in Chicago, the alliance would "set a goal for Afghan forces to be in the lead for combat operations across the country next year".
"I will not keep Americans in harm's way a single day longer than is absolutely required for our national security," Obama said. "But we must finish the job we started in Afghanistan, and end this war responsibly."
BBC Correspondents say Obama's words appear to be aimed at showing American voters he is pursuing a strategy to wind down the war, while reassuring Afghans in the face of a continuing Taliban insurgency.
About 23,000 of the 88,000 US troops currently in the country are expected to leave Afghanistan by the summer, with all US and Nato troops out by the end of 2014.
"It is time to renew America," Obama said towards the end of his remarks.
"My fellow Americans, we have traveled through more than a decade under the dark cloud of war. Yet here, in the pre-dawn darkness of Afghanistan, we can see the light of a new day on the horizon," Obama said.
"The Iraq war is over. The number of our troops in harm's way has been cut in half, and more will be coming home soon. We have a clear path to fulfill our mission in Afghanistan, while delivering justice to al-Qaeda."