Reuters, London :The United States and Britain pledged on Thursday to support Afghanistan’s new unity government as foreign combat troops withdraw from the country after a 13-year involvement.U.S. Secretary of State John Kerry said President Ashraf Ghani’s new government had already made moves to combat money laundering and corruption since taking office in September in the first democratic transfer of power in Afghan history.Ghani, who with former presidential rival Abdullah Abdullah formed a power-sharing government after months of wrangling over election results, sought to reassure allies that he would tackle corruption and stop the theft of aid money.”We are confident that the policies outlined today by President Ghani and CEO Abdullah will result in a more stable and prosperous Afghanistan,” Kerry said at a conference on Afghanistan in London.”This is an extraordinary moment of transition and the possibilities are so enormous,” he added.A 2001 U.S.-led invasion of Afghanistan overthrew the Islamist Taliban who had given sanctuary to al Qaeda. But as most foreign combat troops prepare to leave, local forces are battling a Taliban insurgency.”Let our friends celebrate, let our detractors note that history will not be repeated, that we have overcome the past, we face the future with full unity and with confidence,” Ghani said at the conference, which is not expected to generate new aid.”We hope that we will never need direct combat support because the last thing we want is more war,” he added.British Prime Minister David Cameron stressed the importance of tackling corruption, saying businesses would only invest if Afghanistan could build strong, accountable institutions. A statement at the end of the conference reaffirmed previous donor pledges of $16 billion over four years made at a Tokyo meeting in 2012, but it also emphasized that Afghanistan would not be able to survive solely on domestic revenues.Kerry said the London conference was never meant to be a donor meeting for Afghanistan but to hear from Afghan’s leaders their vision for the country going forward.He said donors could be encouraged by the political progress and reforms to come forward later with new aid.”There will be for sure some effort to increase contributions over time,” Kerry said.But the goal was to make Afghanistan a self-sustaining economy, he said.Days after becoming president, Ghani signed a new security agreement with the United States, a move his predecessor Hamid Karzai refused to do. The agreement lays out the terms under which U.S. troops may stay in Afghanistan. “We are committed to ensuring that Afghanistan can never again be used as a safe haven from which terrorists can threaten the international community,” Kerry said.He, however, said Afghanistan would still face security challenges. “Security will grow, it will get better, but no one should be surprised by attacks that will take place here and there,” he said.