Representatives of six world powers met in Brussels on Friday to discuss possible measures against Tehran for its refusal to halt nuclear enrichment activities and the UN nuclear watchdog chief urged Iran to accept an offer to process its enriched uranium abroad by the end of 2009, and advised Western powers not to impose further sanctions on Tehran. The European Union said senior diplomats from the UN Security Council's five permanent members plus Germany took part in the talks. US President Barack Obama said Thursday the six nations will develop a package of serious new punitive measures in coming weeks. On Wednesday, Tehran indicated it would not export its enriched uranium for further processing, effectively rejecting the latest plan brokered by the International Atomic Energy Agency and aimed at delaying Iran's ability to build a nuclear weapon. On Thursday, Iranian Foreign Minister Manochehr Mottaki played down the threat of sanctions saying embargoes had proved ineffective in the past and that he didn't believe they would be tried again. Meanwhile in Berlin, the head of the UN nuclear watchdog agency said he hoped Iran would not miss the opportunity to resolve its dispute with the international community. “I would hate to see that we are moving back to sanctions,” Mohamed El-Baradei said. “Because sanctions, at the end of the day ... really don't resolve issues.” He said the IAEA had not yet received a formal reply from Tehran to its proposals, although Iranian officials had told him they would not send uranium for reprocessing abroad unless they first received the promised fuel rods. “Well, that to me is an extreme case of distrust,” El-Baradei said. “And what we are really trying to do is replace distrust by a degree of trust.” “I would hope definitely that we'll get an agreement before the end of the year,” he told a news conference in Berlin. “I believe frankly the ball is very much in the Iranian court. I hope they will not miss this unique but fleeting opportunity.”