KABUL — A diminished but resilient Al Qaeda, whose 9/11 attacks drew America into its longest war, is attempting a comeback in Afghanistan’s mountainous east even as US and allied forces wind down their combat mission and concede a small but steady toehold to the terrorist group.

That concerns US commanders, who have intensified strikes against Al Qaeda cells in recent months. It also undercuts an Obama administration narrative portraying Al Qaeda as battered to the point of being a nonissue in Afghanistan as Western troops start leaving.