Iranian President Mahmoud Ahmadinejad was joined by Russian and Chinese officials in a ceremony marking Iran's latest nuclear achievements, the semiofficial Mehr News Agency reports.
Tehran said it secured the uranium from Turkey for use in a research reactor that produces radioisotopes for cancer treatment. Iran's adversaries say Tehran is working on technology needed to produce a nuclear weapon, however.
International inspectors from the United Nations last year said there were possible military dimensions to Iran's nuclear program.
The Iranian report added that a new set of centrifuges was installed at the Natanz enrichment center. The installation means Iran's ability to enrich uranium to 3.5 percent was increased by 50 percent.
Ali Bagheri, deputy chief of Iran's national security council, told Russia's state-run news agency RIA Novosti that the nuclear program in his country was operating under the supervision of the International Atomic Energy Agency.
He added that a letter was on its way to European leaders that contained proposals for a new round of nuclear negotiations with major world powers.
U.S. President Barack Obama had said he'd "take no options off the table" to prevent Iran from developing a nuclear weapon.