The NATO alliance has agreed to hold onto its broad geographic layout of bases in Afghanistan, a move that could make it easier for the United States to keep more troops there as Kabul struggles with a resurgent Taliban threat.
President Barack Obama has planned to slash the number of US forces in Afghanistan from about 9800 to 5500 before he leaves office in 2017, despite calls from former commanders and envoys to halt the drawdown.
NATO defence ministers gathered in Brussels signalled a willingness to stay, with Britain's Michael Fallon saying flatly: "This is the wrong time to walk away from Afghanistan".
He warned any collapse of the country would send thousands more migrants heading to Europe at a time when the continent already faces uncontrolled migration flows.
Mr Fallon told reporters that US Defense Secretary Ash Carter told the ministers during closed-door talks that America troop levels "are being looked at again".
Mr Carter declined to confirm that however, telling a news conference it was "not a topic of discussion" and saying only that Mr Obama would be willing to consider security conditions in Afghanistan and their impact on force levels later in the year.
NATO Secretary-General Jens Stoltenberg said several nations on Wednesday committed to a troop presence next year in Afghanistan, underscoring a theme likely to figure prominently at next month's NATO summit in Warsaw.
"With a regional presence, we will continue to advise, train and assist the Afghan national forces because we are very committed to continuing to support Afghans," Mr Stoltenberg said.
The United States contributes 6800 troops to NATO's training mission in Afghanistan, which will fall to 3400 under the current plan, a NATO diplomat said. Washington also carries out a unilateral counter-terrorism mission in Afghanistan.
NATO's "hub-and-spoke" model for troops training and advising Afghan forces extends well beyond the capital Kabul to allow an international military presence at regional hubs. But NATO policymakers had been examining whether it was possible to keep those posts open, even as force levels fall.