"As we have said before, we will not give up our rights," Ali Akbar Salehi, head of Iran's Atomic Energy Organisation, was quoted as saying by state-owned Iran newspaper on Thursday.

Full details of an enrichment agreement between the Islamic Republic and international powers will be unveiled on Friday, according to Ali Asghar Soltanieh, Iran's ambassador to the International Atomic Energy Authority.

But Salehi said: "There is actually no need for us to enrich uranium to more than four or five percent purity as the reactors that we use need uranium enriched to a maximum of five percent."

"So, enrichment to five percent is the highest level that we want for our reactors. But that does not mean that we will renounce our right to enrich uranium level to a higher level."

Israel Defense Minister Ehud Barak said an enrichment deal would grant legitimacy to Iran to enrich uranium.

"If they don't stop the enrichment, the result is that Iran receives legitimacy to enrich uranium on its soil for civilian purposes, in complete contravention of the understandings reached by those who oppose (Iran) and understand their real goal of acquiring nuclear (weapon) capabilities," Barak told a conference in Jerusalem.

"We recommend to all parties that they not, under any circumstances, take any options off the table," Barak said.

The sole if undeclared nuclear-armed state in the Middle East, Israel has never ruled out a resort to military action to stop Iran achieving a nuclear capability.

Diplomats say the UN atomic watchdog drew up a draft agreement on Wednesday for Russia to process Iranian low-enriched uranium to the 20 percent required by a research reactor in Tehran and for France to turn it into fuel form.

That followed two and a half days of talks in Vienna also involving the United States, where lawmakers unveiled on Thursday a new sanction bill against Iran amid a rising tide of support in the US Congress for imposing fresh sanctions on Iran over its nuclear programme.

"Iran has the capability to enrich uranium to 20 percent but prefers to obtain the fuel from abroad," Salehi said.

"This policy has numerous hidden messages that I would rather not go into," he added.

Salehi said the volume of partly enriched uranium that would be sent abroad under the deal was "not large" and "not a big deal." He did not elaborate.

Diplomats have said the document includes demands that Iran ship out most of its stockpile of low-enriched uranium for further processing by another country.

Uranium enrichment is the sensitive process that lies at the heart of Western concerns about Iran's nuclear programme. It produces fuel for civilian reactors, but in highly extended form can also make the fissile core of an atomic bomb.

IAEA chief Mohamed ElBaradei has asked Iran and the major powers to give their views on the draft by Friday.

In Washington, US lawmakers on Thursday unveiled a new Iran sanctions bill that could bar major global telecommunications giants that do business with the Islamic republic from lucrative US government contracts.

The Accountability for Business Choices in Iran Act, or ABC Iran Act, takes aim at non-US firms that invest or operate in Tehran's energy sector or export "sensitive technology" that could be used by the Iranian government.

The United Against Nuclear Iran advocacy group, which helped write the measure, maintains a list of companies that do business in Iran and notes that telecommunications giants Nokia and Siemens could be affected.

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