Iran, Brazil and Turkey signed an agreement today over a nuclear fuel swap designed to allay international concern over the Islamic Republic's atomic ambitions. Iran said it had agreed to swap 1,200kg of its low-enriched uranium for higher-enriched nuclear fuel, to be used in a medical research reactor. The exchange would take place in Turkey, the foreign ministry spokesman Ramin Mehmanparast said. Iran, which rejects Western accusations it is seeking to develop nuclear bombs, had earlier insisted such a swap must take place on its territory. Turkey and Brazil, both non-permanent members of the UN Security Council, had offered to mediate to find a resolution to the impasse at a time when world powers are in talks to impose a fourth round of UN sanctions on Iran. The Brazilian president Luiz Inacio Lula da Silva and he Turkish prime minister Tayyip Erdogan discussed the deal with the Iranian president Mahmoud Ahmadinejad in Tehran, Iranian state media reported. "The swap will take place in Turkey," Mr Mehmanparast told reporters, shortly before the agreement was signed by ministers in front of reporters. * Reuters