US President Barack Obama has told US troops at Bagram Air Base in Afghanistan that they will have difficult days ahead during their deployment in the country.
"Progress comes slow" and "there are going to be difficult days ahead," Obama told the 3,850 troops at Bagram Air Base, a Press TV correspondent reported on Friday.
The US president landed at the Bagram airbase and prison, located north of the capital Kabul, on Friday and spent a total of four hours on the ground in Afghanistan.
Obama vowed to defeat al-Qaeda and its allies, saying, "We will never let this country serve as a safe haven for terrorists who would attack the United States of America again. We are going to disrupt and dismantle and defeat al-Qaeda and its extremist allies."
"We look forward to a new phase next year, the beginning of a transition to Afghan responsibility," he added.
Obama noted that the allied coalition had grown by six to 49 since his last visit to the country in March, which shows growing support for the Afghan mission.
He spoke to Afghan President Hamid Karzai on the phone during his stay after a video conference was cancelled due to technical problems.
The US president made an unannounced visit to the war zone to thank the troops for serving away from their loved ones at the holidays.
He also promised the troops that they would be exempt from his recently announced freeze on the pay of federal employees.
Washington is expected to complete its review of the Afghan war strategy by late December. Recent polls show that more and more US citizens believe the country should not be involved in the war.