NATO and Afghanistan signed an agreement in Lisbon marking the Atlantic alliance's commitment to the war-torn nation after it ends combat operations, ostensibly by the end of 2014. But a senior U.S. official said some combat troops would stay on beyond that deadline. At a press conference flanked by Afghan President Hamid Karzai and United Nations Secretary-General Ban Ki-moon, NATO Secretary-General Anders Fogh Rasmussen said NATO would not abandon Afghanistan – or the region – even after its forces leave.He spoke minutes after signing an agreement with Mr. Karzai ensuring NATO's long-term presence in that country. Mr. Rasmussen's remarks came as NATO's 28 member states formally agreed to start reducing troop levels in Afghanistan next year and to hand over full control of security operations to Afghan forces by the end of 2014. Mr. Rasmussen said he was confident that deadline could be met, because he said NATO forces were making progress in attacking the Taliban insurgency.