Speaking to Reuters on condition of anonymity, an Iranian source said Iran had written to the EU-3 and emphasised Iran's willingness to "remove existing ambiguities regarding its peaceful nuclear programme through talks and negotitations".
Speaking from Vienna the source said the letter, written by Javad Vaeedi, deputy head of Iran's Supreme National Security Council, was designed to show that "despite the London meeting, Iran is determined to continue talks and to find a solution through talks".
He was referring to a meeting in London on Monday of officials from Britain, China, France, Germany, Russia and the United States to discuss the possibility of sending Iran's nuclear case to the UN Security Council for possible punitive action.
The Iranian source said Vaeedi had pointed out in his letter that Iran was ready to hold talks with the EU-3 on Wednesday as had been scheduled after a previous meeting between the two sides in Vienna last month.
The political stand-off over Iran's nuclear ambitions comes after an international meeting to discuss the possible referral to the UN Security council failed to produce an agreement.
"[Iran is willing to] remove existing ambiguities regarding its peaceful nuclear programme through talks and negotitations"
Iranian letter to EU-3
European, Russian, Chinese and US officials met in London on Monday but, according to a senior German diplomat, could not reach a consensus on the substance of a resolution referring Iran to the Security Council.
Gernot Erler, Germany's deputy foreign minister, told German public television that the countries were still discussing what role the UN should take. He said that would be the main point of discussion at a meeting of the International Atomic Energy Agency (IAEA) planned for early next month in Vienna.
"We remain in talks about what should be decided there and what the role of the United Nations should be," he said.
"That is a sign that we could not reach a full agreement [of] what the goal of the IAEA is through a resolution but that more time is needed."
Meanwhile in separate talks over Iran's nuclear strategy, a delegation of Israeli atomic and security experts was due in Moscow on Tuesday for talks with Russian officials.
An official, speaking anonymously, said: "The visit, which was set up two months ago by Prime Minister Ariel Sharon [before he suffered a brain haemorrhage] is designed to enable an exchange of views and information on the state of play with Iran's nuclear programme."
The delegation includes Giora Eiland, the national security adviser, and Gideon Frank,the head of the country's atomic energy commission.
Russia has offered to enrich uranium for Iran to allay international concern over Tehran's nuclear ambitions.
Moscow has close ties with the Iranian leadership and is building Iran's first nuclear power station at Bushehr, but has expressed concern at Iran's plans to resume nuclear research.
Israel has come to view the regime in Tehran as its number-one enemy following comments in October from Mahmoud Ahmadinejad, the Iranian president, calling for the Jewish state to be "wiped off the map".
Israeli officials have played down the idea of a pre-emptive strike against Iran's nuclear facilities, but Aharon Zeevi, the outgoing head of military intelligence, said last month that such action was "not impossible".
Israel is widely believed to be the only nuclear power in the Middle East, although it has never admitted to possessing nuclear weapons.