Chuck Hagel has made his first visit to Afghanistan as the U.S. secretary of defense.
The unannounced visit to the war zone comes only days after the former senator was sworn in as Pentagon chief, following a bruising battle for confirmation by the U.S. Senate, in which his political adversaries challenged his ability to do the job.
Hagel told reporters traveling with him the purpose of his visit is to thank U.S. troops -- and to learn more about the mission ahead in Afghanistan.
"I need to better understand what's going on there. I need to talk to, listen to, get a good sense from our commanders on the ground. I look forward to reacquainting myself with President Karzai."
Among the difficult subjects on Hagel's agenda when he meets with President Hamid Karzai is the Afghan leader's decision to bar U.S. special operations forces from a key province near Kabul - a restriction that U.S. commanders say will make the job of securing the country more difficult ahead of next year's withdrawal of foreign troops.
The Afghan government's decision follows an earlier ban on airstrikes in populated areas.
The restrictions came after the Karzai government complained that Afghan forces and the U.S. troops supporting them allegedly have committed atrocities against innocent civilians.
Hagel will manage the massive withdrawal of most of the 66,000 U.S. troops and equipment from Afghanistan following an 11-year presence there. At the same time, he said forces will not lose sight of the fact that the war on insurgents is still ongoing.
"We have 66,000-68,000 troops still at war in - in a combat zone. And so that reality is there, must remain there. We'll stay focused on that," said Hagel.
U.S. troops are shifting their focus from a combat role to advising, training and assisting Afghan forces as they transition security responsibility to the Afghans -- a process that is to be completed by the end of 2014.