Washington will continue to press China, Russia and its European allies for a new UN Security Council resolution threatening sanctions against Iran, despite new conclusions that the country ended its nuclear weapons programs years ago, a senior US official said Wednesday. "There is still an enrichment and reprocessing program which is overt," US Undersecretary of State Nicholas Burns told reporters during a visit to Australia. "They still have a ballistic missile development program which the Iranians talk about and boast about." Officials of US President George W. Bush's administration have been forced to defend its strategy on Iran following a new US intelligence assessment that Teheran halted its nuclear weapons program in 2003 - an apparent turnaround on past US conclusions. Secretary of State Condoleezza Rice has been telephoning foreign ministers of US allies such as Germany, Britain and France, as well as their counterparts in China and Russia, which have blocked a recent US push to punish Iran with new sanctions. Burns, who on Wednesday became the first senior US official to meet with Australia's newly elected government, said Washington hoped to make progress on a new Security Council resolution soon. "Our view is that there's every reason for all of us to continue with the efforts in the UN Security Council to continue to offer on the one hand negotiations ... and if Iran cannot support that ... then we believe they should be subjected to a continued sanctions regime," he told a group of reporters. "So we are going to continue to work with the Chinese government, with the Russian government, with France and Germany on a third Security Council sanctions resolution," he said. "And it's important that Iran knows that it cannot just continue these activities of trying to develop scientific capacity on the enrichment and reprocessing side and expect that the world is going to ignore them or allow Iran to continue unfettered," he added. Burns met Australian Deputy Prime Minister Julia Gillard and the country's new foreign and defense ministers, becoming the first senior Washington official to meet the new government since it was elected on November 24.