Nato has moved closer to a limited expansion of its peacekeeping mission beyond the Afghan capital, Kabul.
Kabul is Nato's first major assignment outside Europe
A spokesman said Nato members had accepted political guidelines for extending their role in Afghanistan.
Military planners will now use the guidelines to prepare for action on the ground by the Nato-led International Security Assistance Force (Isaf).
Nato is expected to give the go-ahead once the UN Security Council approves a new mandate for Isaf, diplomats say.
Nato took command of the 5,300-strong international force in August.
Isaf troops have been confined to Kabul since they were sent to Afghanistan after US-led troops ousted the Taleban nearly two years ago.
Security has been steadily deteriorating in the provinces in recent months.
Afghan President Hamid Karzai and United Nations Secretary General Kofi Annan have both called for the peacekeeping mission to be expanded to improve security outside the capital.
Of particular concern is the need to protect elections due to be held next year.
The Nato decision was taken by so-called silence procedure, under which the 19 member nations had until Monday morning to raise objections to plans to expand the peacekeepers' remit.
None did, so agreement was confirmed.
Under the plans being considered, about 400 German troops would be sent to the northern region of Kunduz.
A Nato official said planning for the mission was "pretty advanced" and Secretary General Lord Robertson would be advising the UN to proceed with preparing the necessary resolution.
Isaf is separate from the US-led operation which continues to fight
Taleban remnants and their al-Qaeda allies in southern and eastern Afghanistan.