Diplomats say the U.N. nuclear agency has denied Iran's request to help complete a plutonium reactor that the United States and others fear could yield material for a nuclear weapon.
But the diplomats say the International Atomic Energy Agency left room for Iran to renew the request at a later time. Several developing nations supported providing aid for the Arak reactor.
Iran has ignored earlier calls by the IAEA to stop building the reactor. Tehran says the Arak site will open in 2009, even without foreign aid.
In August, Iran defied a U.N. deadline to stop enriching uranium at a separate nuclear site. Western nations are pressing for sanctions against Iran at the U.N. Security Council because of the decision. Iran says its nuclear program is for peaceful purposes.
Some information for this report was provided by AFP, AP and Reuters.