US and Nato troops have fully withdrawn from Bagram Air Base, officials said on Friday, completing a low-key departure from a sprawling military facility that was synonymous with the American presence in Afghanistan for two decades. Among the countless items left behind was a piece of the World Trade Centre that New York firefighters buried 20 years ago, after the attacks of September 11, 2001 led to the US-led invasion to topple the Taliban, who had harboured Al Qaeda. "All American soldiers and members of Nato forces have left the Bagram air base," a senior US security official said on condition of anonymity. Officially US involvement in Afghanistan will end by September 11, but the withdrawal from Bagram, where the US coordinated much of its 20-year war effort, effectively puts a capstone on the longest war in American history. Pentagon press secretary John Kirby said on Friday that Defence Secretary Lloyd Austin has approved a new command structure in Afghanistan to transition the US military mission from combat to two new objectives – protecting a continuing US diplomatic presence in Kabul and maintaining liaison with the Afghan military. Under the plan, the top commander in Afghanistan, Gen Austin Miller, will transfer his combat authorities to the Florida-based head of the US Central Command, Gen Frank McKenzie, before relinquishing his command this month. A two-star Navy admiral will head a US Embassy-based military office, to be known as US Forces Afghanistan-Forward, which will oversee security for the embassy and its diplomats. A satellite military office based in Qatar and headed by a US one-star general will be set up to administer US financial support for the Afghan military and police, plus maintenance support for Afghan aircraft from outside Afghanistan, Mr Kirby said. <br/> About 1,000 troops will remain in Afghanistan for now – most of them to guard the massive US Embassy in the heart of Kabul's Green Zone, the rest to help secure Kabul's international airport until a deal with Turkey to protect the facility can be finalised. An hour's drive north of Kabul, the Bagram base was where the US military has organised its air war and logistical support over the past two decades. The Taliban thanked them for leaving. "We consider this withdrawal a positive step. Afghans can get closer to stability and peace with the full withdrawal of foreign forces," Taliban spokesman Zabihullah Mujahid said. Other Afghans were more circumspect. "The Americans must leave Afghanistan and there should be peace in this country," said Kabul resident Javed Arman. But he added: "We are in a difficult situation. Most people have fled their districts and some districts have fallen. Seven districts in Paktia province have fallen and are now under Taliban control." <br/> For the international forces, more than 3,500 of whom died in Afghanistan, the exit came with no pageantry. A Western diplomat in Kabul said the United States and its Nato allies had "won many battles, but have lost the Afghan war". It was at Bagram, by a bullet-ridden Soviet-built air strip on a plain hemmed in by the snow-capped peaks of the Hindu Kush, that New York City firefighters and police were flown to bury a piece of the World Trade Center in December 2001, days after the Taliban were toppled for harbouring Osama bin Laden. It was also here that the CIA ran a "black site" detention centre for terrorism suspects and subjected them to abuse that former president Barack Obama subsequently acknowledged as torture. Later it swelled into a sprawling fortified city for a huge international military force, with gyms and a cafe serving something called "the mother of all coffees". Over the years, Bagram has hosted hundreds of thousands of US and Nato service members and contractors. Facilities included swimming pools, cinemas and spas – and even a boardwalk featuring fast-food outlets such as Burger King and Pizza Hut. Two runways perpetually roared. Presidents flew in and gave speeches; celebrities came and told jokes. An Afghan official said the base would be officially handed over to the government at a ceremony on Saturday. Earlier this week, Gen Miller told journalists in Kabul that civil war for Afghanistan was "certainly a path that can be visualised", with Taliban fighters sweeping into districts around the country in recent weeks as foreign troops flew home. Two other US security officials said this week the majority of US military personnel would most likely be gone by July 4. On Friday, Mr Biden said the drawdown of US troops from Afghanistan is on schedule but would not be completed in the next few days. "We're on track exactly as to where we expect to be," he said. Speaking to reporters at the White House, he said he was confident that Afghan leaders had the capacity to sustain the government but was concerned about internal issues. Questions also remain about the fate of thousands of Afghan interpreters and other workers who assisted the US military – including many from Bagram. The Biden administration has pledged to expedite their visa requests. Washington agreed to withdraw in a deal negotiated last year with the Taliban under Mr Biden's predecessor Donald Trump, and Mr Biden rejected advice from generals to hang on until a political agreement could be reached between the insurgents and the US-backed Kabul government of President Ashraf Ghani. Last week, Mr Ghani visited Washington, where Mr Biden told him: "Afghans are going to have to decide their future, what they want". The Afghan leader said his job was now to "manage the consequences" of the US withdrawal. The Taliban viewed the deal signed with the Trump administration as proof they had won the war and immediately stepped up attacks on the beleaguered, under-resourced and corrupt Afghan security forces. In the past two months, Taliban insurgents have launched offensives across Afghanistan, seizing dozens of districts as Afghan security forces have largely consolidated their power in the country's major urban areas. The Taliban gains have raised fears the Taliban will seize power within months of foreign forces leaving the country and western diplomats hold out little hope the Afghan security forces will be able to fend for themselves. Bagram became the staging point for the Soviet invasion of the country in 1979, and the Red Army expanded it significantly during its near decade-long occupation. When Moscow pulled out, it became central to the raging civil war – it was reported that at one point the Taliban controlled one end of the three-kilometre runway and the opposition Northern Alliance the other. In recent months, Bagram has come under rocket attacks claimed by the Afghan branch of ISIS, stirring fears that militants are already eyeing the base for future attacks. <br/> <br/> <br/> <br/>