"The project on manufacturing the 20% enriched fuel plates necessary for the Tehran research reactor is in its final stages," aide Mojtaba Samareh Hashemi said

Earlier on Tuesday, the ISNA news agency, citing a top official, reported that Iran will continue enriching uranium to 20% to fuel "four to five" nuclear research reactors it intends to build in the "next few years".

"In the next few years, four to five (research) reactors... of 10 to 20 megawatts will be built," the head of Iran's atomic energy organisation, Fereydoon Abbasi Davani, said.

The aim of the new reactors is "to produce radio isotopes, and (to enable) research and development," he said.

Iran is under four sets of U.N. Security Council sanctions, primarily for defying council demands to stop uranium enrichment, but also because of a record of nuclear secrecy.

The U.S. and other Western countries accuse Iran of developing nuclear weapons under the cover of peaceful nuclear energy program. Tehran denies all the charges, saying that its nuclear program is focused on the country's electricity needs.