US to sign strategic pact with Afghanistan Afghan President Hamid Karzai shakes hands with US President Barack Obama after signing a strategic partnership agreement at the Presidential Palace in Kabul President Barack Obama made an unannounced visit to Afghanistan on Tuesday, where he will meet his counterpart Hamid Karzai and sign a long-term strategic agreement between the two countries. The visit by Mr Obama, who was due to give a television address on Tuesday evening to the American people about the war in Afghanistan, is designed to signal continued US support for the country after the bulk of Nato forces leave in 2014. IN Afghanistan Mr Obama's trip to Afghanistan also comes after a tumultuous period for relations between the two countries, including the alleged mass killing of 17 Afghans by a US soldier and the deaths of a number of Nato soldiers at the hands of Afghan counterparts. Under the existing mission, the US and other Nato forces in Afghanistan are due to leave the country in 2014 after handing over security responsibilities to Afghan forces. Mr Obama was to formally sign an agreement, which was concluded 10 days ago, with the Afghan government and which allows for some US troops to remain until 2024, mostly special forces. The new agreement is designed to reassure the Afghan public, other powers in the region and insurgent groups that the US will not abandon the government in Kabul when most of the troops leave and that it will retain the capacity to launch military operations against militants. The Obama administration hopes that the agreement, which was reached after fraught negotiations over the control of military prisons and the use of night raids on insurgents, will reduce the risk that Afghanistan will lurch back into civil war after 2014. The president arrived in Afghanistan on the same day that the Pentagon warned of "long-term and acute" challenges in the country after more than a decade of war, though levels of violence had declined. In a twice yearly report on the conflict that the US military prepares for Congress, the Pentagon said that the Taliban remained a "resilient and determined enemy," while Mr Karzai's government still had only "limited capacity." According to the report, violence in Afghanistan decreased by 9 per cent in 2011, compared to the year before, although violence did increase around the Taliban stronghold of Kandahar. The surge of an extra 33,000 troops that Mr Obama ordered in 2009 had allowed the US and its allies to move from a position of "essentially losing the war to making important progress," the report said.