UN inspectors revisited Iran's second uranium enrichment facility Thursday, diplomats said, after voicing concern that Tehran's belated disclosure of the nuclear site meant more may be hidden away. The inspection came amid US warning. World powers could have a package of measures against Iran “within weeks”, US President Barack Obama said, warning Tehran of consequences for its failure to respond to an offer of a nuclear deal. Representatives from major world powers will meet in Brussels Friday to discuss developments with Iran's nuclear programme, EU foreign policy chief Javier Solana's office said Thursday. “I can confirm to that tomorrow in Brussels there will be a meeting of the three plus three at the level of political directors, hosted by the European Union,” Solana's spokeswoman said. Meanwhile, the UN inspectors aimed to make further checks of the Fordow site's layout and wanted more Iranian explanations to pinpoint the project's chronology and original purpose, as well as access to its director and designers. Iran on Wednesday rejected a deal to send enriched uranium abroad for rendering into fuel for medical purposes in Tehran, defying world powers which regarded the offer as a way to delay Iran's potential ability to make atomic bombs by at least a year by divesting the country of most of its refined uranium stock. Under the plan brokered by the UN nuclear watchdog, Iran would ship some 75 percent of its low-enriched uranium to Russia and France, where it would be converted into fuel plates for a Tehran reactor that makes isotopes for cancer treatment. “Iran has taken weeks now and has not shown its willingness to say yes to this proposal ... and so as a consequence we have begun discussions with our international partners about the importance of having consequences,” Obama said at a joint news conference with South Korean President Lee Myung-bak in Seoul. In apparent response to Obama's comments, Iran's President Mahmoud Ahmadinejad reiterated in a speech in Tabriz that Iran would respond positively to a change in big powers' policy. He demanded that world powers respect Iran and release its assets if they want to engage with Tehran.