Eight US soldiers were killed in Afghanistan at the weekend in the deadliest attack on US forces in more than a year, intensifying the debate in Washington on the best course of action.

The Taliban assault on a mountain outpost near the Pakistan border was the latest in a series of increasingly devastating attacks on Nato forces and one of the fiercest battles of the eight-year Afghan war. It came as the Obama administration arrived at a crossroads in its Afghan policy with senior officials and congressmen calling for the war effort to be scaled back amid increasing public disquiet.