Rasmussen met Monday in Kabul with Afghan President Hamid Karzai. Members of the NATO-led International Security Assistance Force are wrapping up combat operations there as Afghan forces take more control over security in the country.
"This is a great responsibility but Afghanistan's forces have shown they can rise to the challenge and they will continue to have our support," said Rasmussen.
Rasmussen said the alliance was committed to its support for Afghan forces after ISAF ends formal combat operations at the end of next year.
Though 87 percent of the country where Afghans reside is under Afghan military control, the Rasmussen said NATO forces were working to set up a new training mission to serve in Afghanistan after combat operations end.
"That mission will be called Resolute Support, because our support for Afghanistan remains steadfast," he said in a statement.
A U.N. report on Afghanistan said that while civilians continue to fall victim to insurgent attacks, the number of war-related deaths is declining.