Kabul, Dec 28 (IANS): The NATO-led International Security Assistance Force (ISAF) Sunday formally ended its 13-year-old combat mission in Afghanistan.

In a ceremony held here, US commander of ISAF General John F. Campbell said: "Today marks an end of an era and the beginning of a new one."

"We remember and honour those coalition and Afghan heroes whom we've lost and the loved ones they left behind," Xinhua quoted the general as saying.

"Their sacrifices drive us to persevere. They drive us to finish this noble mission well, they drive us to win."

Ruling out the possibility of Taliban returning to power, Campbell said: "There is no turning back to the dark days of the past."

"We are not walking away. It's time for the enemy to heed President Ashraf Ghani's call, lay down their arms, embrace peace and help rebuild the Afghan nation."

Speaking at the ceremony, Afghan presidential advisor on national security Mohammad Hanif Atmar appreciated the services of NATO-led troops in Afghanistan.

During the past 13 years, more than 3,500 servicemen, some 2,200 of them Americans, have lost their lives in Afghanistan.

With the combat mission of the NATO-led forces ending, the transition of the alliance to Afghan national security is completed and Afghan forces formally assume the security responsibility of their country from Jan 1, 2015.

However, some 13,000 NATO servicemen, including 10,800 Americans, are to remain in Afghanistan in 2015 to train and advise Afghan national security forces.