Assad has said it would not be difficult to agree on a new government including opposition figures, but his opponents responded on Wednesday that no administration would be legitimate while he remained in office. Assad, bolstered by military victory in the desert city of Palmyra, was quoted by Russia's RIA news agency as saying a new draft constitution could be ready in weeks and a government that included opposition, independents and loyalists could be agreed. While the distribution of portfolios and other technical issues would need to be discussed at Geneva peace talks, which resume next month, "these are not difficult questions", Assad said. Opposition negotiators immediately dismissed Assad's remarks, saying that a political settlement could be reached only by establishing a transitional body with full powers, not another government under Assad. "What Bashar al-Assad is talking about has no relation to the political process," said George Sabra of the High Negotiations Committee. The United States also rejected Assad's comments. "I don't know whether he envisioned himself being a part of that national unity government. Obviously that would be a nonstarter for us," White House spokesman Josh Earnest said. Syria's crisis erupted five years ago with protests against Assad which were put down with force. It descended into a civil war which has killed more than 250,000, drawn in global military powers and helped Daesh (so-called IS) establish its self-declared caliphate. Nearly five million refugees have been driven abroad. Economic costs of war At a conference in Geneva, UN Secretary-General Ban Ki-moon called on countries to resettle nearly half a million Syrian refugees in the next three years. "This demands an exponential increase in global solidarity," he said, though his appeal won immediate responses from only three countries - Italy, Sweden and the United States. Assad told RIA the war had cost more than $200 billion in economic losses and damage to infrastructure. That is in line with a UN-backed body which estimates physical damage at $90 billion, with an additional $169 billion of accumulated losses from a collapse in GDP to less than half the 2011 level. Despite Assad's upbeat assessment of the chances for a political solution, his comments reflected deep differences with the opposition. It says that for the last four years international agreements on Syria's future have centered on the principle of setting up a transitional governing body. Assad's opponents have understood that such a body would have full powers, and that he would not play a further role. But the president said the very idea of a transitional body was "illogical and unconstitutional". "That's why the solution is forming a national unity government which prepares for a new constitution," he said, adding that its formation would be agreed in Geneva.