President Barack Obama has urged the US Congress not to trigger new sanctions against Iran over its nuclear programme, saying that such a development could upset diplomatic talks and potentially lead to war.<br /><br /> In a joint news conference at the White House, he was backed by British Prime Minister David Cameron, ending a two day trip to Washington. Cameron said he had personally called US senators about the issue.<br /><br /> Obama said he had told Democratic lawmakers that he would veto a bill calling for new sanctions if it landed on his desk.<br /><br /> “There is no good argument for us to try to undercut, undermine the negotiations until they have played themselves out,” Obama told reporters. <br /><br /> “But Congress should be aware that if this diplomatic solution fails, then the risks and likelihood that this ends up being at some point a military confrontation is heightened.”<br /><br /> Talks between six world powers and Iran failed to meet a self-imposed deadline for a solution in November. Obama put the chances of
