Russian President Dmitry Medvedev said on Friday Lula's trip was seen by Western and Russian authorities as the last opportunity for a diplomatic resolution to the international dispute over the Iranian nuclear program.

Brazilian President was set to discuss a proposed uranium swap as part of international efforts to settle questions surrounding Iran's nuclear program without resorting to further sanctions.

However, Haaretz said that Iranian officials and media ignored the nuclear issue in public and instead focused on mutual relations.

"Your trip enjoys a special importance due to the onset of serious cooperation between the two great nations and also because many countries are awaiting our added cooperation," state television quoted Ahmadinejad as saying during a meeting with Lula.

The paper said Brazilian President has also met with Iran's most powerful authority Supreme Leader Ayatollah Ali Khamenei, whose opinion on all state matters like Iran's nuclear activities is highly important.

"America is angry over the proximity of independent countries like Iran and Brazil...That is why they made a fuss ahead of your trip to Iran," state television quoted Khamenei as saying to Lula.

Medvedev specified several principles that a legitimate Iranian nuclear program would have to adhere to: it should be peaceful in character and supervised by the International Atomic Energy Agency (IAEA), and Iran should cooperate with the international community and follow the rules of nuclear non-proliferation.

According to Medvedev, Iran will take its place among the nuclear-operating countries if it follows the previously called principles.

The United States and other Western countries suspect Iran of developing nuclear weapons under the guise of a civilian nuclear energy program and are seeking new sanctions following Iran's move to enrich uranium to 20%.

The Iran Six (France, Britain, Germany, the United States, Russia and China) began on April 19 discussing the text of a draft resolution imposing sanctions on Iran over its controversial nuclear program.

Russia and China, who have the right to veto Security Council's decisions, insist on resolving Iran's nuclear issue peacefully, but the United States, Britain, France and Germany are pushing for harsher sanctions against the Islamic Republic.

Iran was under international pressure to halt uranium enrichment, needed both for electricity generation and weapons production. Tehran has repeatedly rejected the demand, insisting it is pursuing a purely civilian program. Several Western powers have called for harsher sanctions against Tehran if it does not agree to halt uranium enrichment.