Salehi said Iran is seeking objective guarantee for the nuclear fuel swap, referring to the exchange should be carried out "simultaneously and inside Iranian territory," according to the report on a press conference held by Russian Energy Minister Sergei Shmatko (L) and the head of Iran's Atomic Energy Organization Ali Akbar Salehi in Tehran.

Though Iran is making good progress in enriching uranium with the purity of 20 percent, it has written a letter to the International Atomic Energy Agency (IAEA) demanding countries which have the capacity supply 20 percent purity fuel for a Tehran medical research reactor, Salehi said.

Under a draft deal brokered by the international nuclear watchdog IAEA, most of Iran's existing low-grade enriched uranium will be shipped to Russia and France, where it will be processed into fuel rods with a purity of 20 percent. The higher-level enriched uranium will then be transported back to Iran.

Iran rejected the deal, urging for a simultaneous swap of the fuel on its soil.

Iran's foreign minister said on April 20 that a nuclear fuel swap can build trust for all sides involved, local satellite Press TV reported.

A nuclear fuel swap deal can provide an opportunity for confidence-building between Iran and West over Tehran's nuclear energy program, Manouchehr Mottaki said.

"We think that if the other sides have a true will to materialise the nuclear swap deal, it can become a multilateral confidence building measure for all sides," Mottaki was quoted as saying at the press conference.

Xinhuanet