Speaking at the start of a critical week of high-stakes diplomacy, Foreign Minister Sergei Lavrov said the five permanent UN Security Council members and Germany were hammering out a plan for resumption of talks with Tehran.

"We are prepared to guarantee Iran's right to peaceful nuclear energy on the condition it answers the questions the IAEA has raised," Russian news agencies quoted him as saying, referring to the Vienna-based International Atomic Energy Agency (IAEA).

In Vienna, diplomats said foreign ministers from the UN permanent five -- Britain, China, France, Russia and the United States -- and Germany planned to meet there Thursday.

The meeting has not yet been confirmed, they cautioned, but one European diplomat said that it was being arranged to "fine-tune" an EU-drafted package of incentives to get Iran to guarantee it will not make nuclear weapons, as well as sanctions if Tehran does not comply.

Political directors from the six foreign ministries will Tuesday discuss the package in a telephone conference, diplomats in Vienna confirmed.

The United States suspects Iran is working secretly toward building its own nuclear weapons under cover of a civilian drive for atomic power, and accuses Tehran of failing to cooperate with the IAEA.

Iran denies these charges, saying its nuclear work is confined strictly to generating energy and insisting that it has always cooperated with the IAEA.

As Lavrov spoke, Iran stressed that it would pursue its uranium enrichment work -- the process that makes fuel for reactors but also what can be the raw material for atom bombs.

"Enrichment will continue on Iranian territory within the framework of Iran's peaceful nuclear programme and the IAEA," government spokesman Gholam Hossein Elham told reporters in Tehran.

In Malaysia, visiting Iranian Foreign Minister Manouchehr Mottaki said any new incentive from the European Union that did not acknowledge Iran's right to develop nuclear energy on its own would be a non-starter.

"The main incentive for Iran is to recognise the essential right of Iran to have nuclear technology and the ways of realising this right," Mottaki said.

Lavrov's comments however suggested that some kind of consensus among the world's top powers on how to deal with widespread concern over Iran's nuclear ambitions may be taking shape.

Referring to all six major world powers involved in efforts to resolve the standoff, Lavrov stated: "We are ready and mutually interested in drawing Iran into full economic cooperation as well as in cooperation in regional security."

He did not elaborate, but foreign policy experts in Russia, Europe and the United States have said for months that the key to breaking the deadlock lies in economic incentives and practical security assurances from the West.

In Vienna, a Western diplomat said the EU negotiating troika of Britain, France and Germany "are working hard now to revise their package to respond to concerns, mostly from Russia and China."

The diplomat said disagreements centered around the timing of any Security Council resolution to require Iran to comply and open the door to sanctions, with Russia and China wanting to put this off but the United States and Europe wanting sanctions to quickly follow any Iranian non-compliance.

"There are still significant areas of disagreement" such as "the detail and commitment in the package to a specific menu of sanctions," the diplomat said.

According to a draft text seen by AFP, the possible sanctions include an arms embargo on Iran -- something Russia, a major arms supplier to Iran, and China, a major consumer of Iranian oil, resist.

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