In a statement released after a meeting of NATO and Russian foreign ministers, Rasmussen said a decision on the draw-down of Afghan security forces has not been decided and will depend on the situation in the country.
"Together with the rest of the international community we will play our part and pay our share in sustaining Afghan security forces at the right level for years to come," his statement said.
The meeting in Brussels failed to come up with a clear timetable for the West's exit from Afghanistan.
Afghan Defense Minister Gen. Abdul Rahim Wardak said no one can predict what the situation will be after 2014.
"Going lower on troop numbers has to be based on realities on the ground," he said. "Otherwise, it will put at risk all that we have accomplished together with so much sacrifice."
In his report on the meeting, Rasmussen said the NATO-Russia Council has trained 2,000 counter-narcotics personnel from Afghanistan and neighboring states.
Afghan helicopter maintenance engineers are currently starting training in Russia in a program financed by the council.