The departure of the 33,000 troops was completed ahead of an end of September deadline set by American President Obama, as the international allies prepare to pull out all combat troops by the end of 2014.
The American president ordered the surge of reinforcements in December 2009 after a review of the Afghan campaign by Gen Stanley McChrystal warned that the coalition would fail without more troops, The Telegraph reported Saturday.
Leon Panetta, the US defence secretary, declared the surge had achieved its objectives and said the departure was a “very important milestone”.
“The surge did accomplish it objectives of reversing the Taliban momentum on the battlefield and dramatically increasing the size and capability of the Afghan national security forces,” he told reporters during a visit to New Zealand.
But he spoke after a difficult week for the coalition, as the Taliban mounted a spectacular attack on Camp Bastion which caused hundreds of millions of dollars of damage to aircraft.
The coalition has also had to temporarily scale back joint operations with Afghan police and soldiers because of the risk of more “green on blue” shootings, which are now causing one-in-six of all Nato deaths.
The surge poured into Helmand province, where under-strength British forces had been fought to a stalemate, and to Kandahar, the birthplace of the Taliban movement.
Residents and officials say security has improved in both those provinces, though violence continues. Security has meanwhile worsened elsewhere in the east and it is unclear how long-lasting the improvements may be as troops go home.
Surge forces also helped train and advise the Afghan police and army as they have grown rapidly in the past three years.
Simon Gass, the Nato civilian envoy to Afghanistan, earlier this week said the Taliban remained resilient and he predicted that without a peace deal, they would still be fighting after the coalition withdrew.
Both American and British generals have lobbied for the coalition force to now stay at its current level for 12 months. Politicians faced with growing war weariness at home are expected to defy their calls and continue the withdrawal through 2013.
British troops have so far pulled out more slowly than the Americans and 9,500 remain; from a peak last year of slightly over 10,000.
David Cameron is widely expected to order a withdrawal of several thousand British troops next year.
