The review affirms Obama's strategy of paving the way for troop withdrawals beginning in July 2011 and says the challenge is in maintaining gains against insurgents. It also calls for adjusting U.S. strategy for Pakistan.A long-awaited White House review of the U.S. troop buildup in Afghanistan lays claim to progress in the fight against the Taliban insurgency, but it also acknowledges challenges to building a stable Afghan government and in eliminating militant sanctuaries in Pakistan.