The United States is no closer to achieving its goals in Iraq than it was a year ago but a quick military withdrawal could lead to massive chaos and even genocide, according to a report released Sunday by a US think tank. The US Institute of Peace report was written by experts who advised the Iraq Study Group, a panel mandated by Congress to offer recommendations on US policy in Iraq in 2006. The report was released two days before top commander Gen. David Petraeus and Ambassador Ryan Crocker brief Congress on the situation in Iraq and prospects for American troop reductions. Their recommendations, which US President George W. Bush has signaled he will accept, could largely determine the course of action in Iraq for the coming year. The report cited security improvements in Iraq since the buildup of US forces in 2007, but credited factors outside US control, such as help from mostly Sunni fighters who turned against al-Qaida and a truce by a Shi'ite militia.