Obama to 'accelerate' Afghan withdrawal In another important concession for Mr Karzai, the US has also agreed that detention facilities in Afghanistan would fall under Afghan sovereign control "soon after" Mr Karzai's departure Friday night. Control of detainee centres, particularly those at the symbolic Bagram Air Base outside Kabul, has been a major sticking point for Mr Karzai. Shuja Nawaz, director of the South Asia Centre at the Atlantic Council said the decision to hand then over provided him with a face-saving victory for Mr Karzai to take home from his three-day visit to Washington. "The Afghans see the prison issue as a major symbol and the US should take that seriously," he added. Mr Karzai also received agreement from the US to set up a Taliban office in the Qatari capital, Doha, to facilitate possible peace negotiations with Taliban. Negotiations are expected to continue until November over how many international troops will remain in Afghanistan after 2014, and Mr Obama declined to speculate over the size of any force. However Mr Obama made clear that no US troops could remain in Afghanistan if Kabul did not agree that US soldiers would be immune from prosecution under Afghan law. Mr Karzai, who said he would retire after next year's Afghan elections, said that concessions over prisoner detentions and the decision to remove US forces from Afghan villages would help him sell the idea of immunity to the Afghan people. Mr Karzai arrived in Washington earlier this week to urge the Mr Obama to commit to securing Afghanistan beyond 2014. The Afghan president was understood to want both US personnel and material support, including tanks, unmanned drones and aircraft at time of tightening US finances and even though the war has already cost $600 billion. Before talks began, a White House spokesman said it had ruled out nothing, including a "zero option" that would leave no troops behind after 2014. "If President Obama had one wish on a magic lamp I think it would be to be out of Afghanistan yesterday," added Mr Nawaz, of the Atlantic Council said. At the same time, the administration and its Coalition allies, including the UK, have to balance the desire to cut costs with the risk that leaving too soon would increase the risks from of a resurgent Taliban, and even civil war. Gen John Allen, the US commander in Afghanistan, is reported to have presented Mr Obama with three potential post-2014 scenarios that would leave 6,000, 10,000 or 20,000 American troops remaining. Mr Karzai told a meeting at the Pentagon that he could assure the American people that his country "will not ever again be threatened by terrorists from across our borders."