Iran has called on the West to look to lifting its sanctions if it wants to quickly resolve the showdown over Tehran's disputed nuclear activities, a prospect swiftly ruled out by Washington.

Foreign Minister Ali Akbar Salehi outlined his country's message in an interview with the news agency ISNA on Monday, following milestone talks at the weekend in Istanbul between Iran and world powers.

Those talks, described by both sides as an encouraging revival of a process that had been moribund for 15 months, are now due to be developed in another, more substantive round on May 23 in Baghdad.

"If the West wants to build trust, it should begin with sanctions, because it can help speed up the talks reaching a solution," Salehi was quoted as saying.

"If goodwill (from the West) is present... we are ready to rapidly and easily, and even in the Baghdad meeting, resolve all issues" regarding Iran's nuclear programme, he said.

The foreign minister appeared to suggest that the level of enrichment could be up for discussion.

However US Secretary of State Hillary Clinton, during a trip to Brazil Monday, insisted that the "burden of action" is with Iran to prove it is serious in nuclear talks, dismissing Tehran's appeals for world powers to ease sanctions first.

"The burden of action falls on the Iranians to demonstrate their seriousness and we're going to keep the sanctions in place and the pressure on Iran" as Tehran prepares for the talks in Baghdad next month, Clinton said in Brasilia.

"And we'll respond accordingly," she added following the talks at the weekend in Istanbul between Iran on one hand and the United States, China, Russia, France, Britain and Germany on the other.

While Iran's negotiators will take the position in Baghdad that producing 20 percent enriched uranium "is our right," foreign minister Salehi said, if the world powers "guarantee they will provide us with fuel of various purities, it will change the perspective."

Iran currently enriches uranium to 3.5 percent and to 20 percent. The former it says is to power its Bushehr nuclear electricity plant and the latter it says is to generate medical isotopes in its Tehran research reactor.

Uranium has to be enriched to 90 percent or above for use in an atomic bomb.

Salehi's comments could add impetus to the Baghdad round of talks, especially as the West has so far made no mention of previous demands that Iran halt all uranium enrichment -- a demand also stated in UN Security Council resolutions.

The international sanctions, sharply ramped up this year, target Iran's all-important oil export sector and are seen by many Western capitals as a key reason why Tehran was willing to resume its negotiations with the so-called P5+1 group comprising the five permanent UN Security Council members plus Germany.

By the beginning of July, the United States and the European Union are due to fully implement economic sanctions they have already started -- unless some sort of breakthrough is made in the talks.

Russia's foreign ministry, however, said in a statement Monday that Moscow does not back increasing "sanction pressure" on Tehran.

Russian Foreign Minister Sergei Lavrov "confirmed the unacceptability of the prospect of Tehran obtaining nuclear weapon potential", in a meeting with visiting Israeli National Security Council director Yaakov Amidror, it said.

But he slammed as "counterproductive and dangerous any attempts to use reports of Iran's nuclear technology progress to artificially whip up tensions around Iran and create an excuse for further build-up of sanction pressure."

The United States and many of its EU allies believe that Iran has been working towards developing a nuclear weapons capability -- a suspicion given weight by the UN's International Atomic Energy Agency.

But Iran insists that its nuclear programme is entirely peaceful, and its supreme leader, Ayatollah Ali Khamenei, has called the possession of atomic weapons "a great sin."

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