NATO Secretary General Jens Stoltenberg says "re-energising" peace talks is the only way of reaching an acceptable solution for Afghanistan.
A decision could be taken on Thursday by NATO defence ministers on the US-Taliban peace deal, which says all international troops should leave by May.
Germany's Defence Minister Annegret Kramp-Karrenbauer says peace talks, which are key to the deal, have not made enough progress to allow further international troop withdrawals.
The Afghan government is reported to have asked for troops to stay for another two years.
Jens Stoltenberg said: "We are calling on [the] Taliban to reduce violence, to negotiate in good faith and to stop supporting international terrorists like Al Qaeda.
"Our presence in Afghanistan is conditions-based and [the] Taliban has to meet the commitments.
"We will only leave when the time is right and our focus now is how can we support the peace efforts, the peace talks.
"We went into Afghanistan together, NATO allies, partners and the United States after 9/11, we have made decisions on adjusting our presence together and we will also make decisions when the time is right on leaving together."
Cover image: Library picture showing an aerial view over mountains in Afghanistan (Picture: US Army).