There are fears that insurgents who already operate in half of Afghan territory could take more ground.
But in Brussels any suggestion of a US withdrawal is played down.
“The Resolute Support Mission remains unchanged,” said the chairman of NATO’s military committee, Air Chief Marshal Sir Stuart Peach.
“And we have confirmed our commitment to the safety and security of Afghanistan and we've confirmed our commitment to the force generation process by which we create up to 41 allies and partners support the mission.
"So there has been no change and if there is further change that would be a matter for the US authorities.”
A wholesale end to KFOR in response looks unlikely but there could be some changes.
“We continue and we’ve made clear publically, as the Secretary General has, that we will re-examine our engagement with the Kosovo Security Force should the mandate evolve," said Air Chief Marshal Peach.
“And that position remains unchanged and in our mission in Kosovo we continue to operate under a United Nations mandate which is not affected by any change in the transition of the Kosovo Security Force.”
The NATO Defence Chiefs can only advise and translate political aspirations into action.
Decisions won't begin to be made until NATO Defence Ministers meet in Brussels in February.