WASHINGTON (Reuters) - The head of U.S. and international forces in Afghanistan said on Monday the United States’ future presence in Afghanistan would be based on “conditions and not arbitrary timelines”. “This new strategy means the Taliban cannot win militarily. Now is the time to renounce violence and reconcile,” General John Nicholson said in a statement. President Donald Trump opened the door on Monday night to an increase in U.S. troops in Afghanistan as part of a retooled strategy for the region, overcoming his own doubts about America’s longest war and vowing “a fight to win.” 