NATO could decide in February whether to end its two decades of military presence in Afghanistan.
The head of the alliance told an online meeting of foreign ministers on Wednesday they face a turning point early next year.
NATO Secretary General Jens Stoltenberg said: "What we need to see is a lasting peace agreement, and part of that has to be a ceasefire so the reduction of violence should only be the first step.
"The ambition is an inter-Afghan peace solution.
"There is a price for staying longer but there is also a price for leaving too soon," he added.
"We will have to take some hard decisions when NATO defence ministers meet next February but whatever we decide, we must do it in a coordinated and orderly way."
The US will reduce the number of its troops in Iraq and Afghanistan by mid-January 2021, the country's Acting Defense Secretary Christopher Miller said last month.
Soon after, UK Defence Secretary Ben Wallace confirmed the number of British troops in Afghanistan could also be reduced if the United States goes ahead with its own reductions in the country.
However, a few days after the announcement at the end of November, mortar fire killed eight people and injured more than 30 others, as it struck a residential area of Kabul, reports suggested.
The attack came just hours before outgoing US Secretary of State Mike Pompeo held what is likely his last peace meetings in Qatar, with the Taliban and Afghan government negotiators.
About 11,000 NATO troops, including 850 from the UK, are currently in Afghanistan.