Iran's foreign minister said he hoped a "roadmap" for negotiations could be reached in nuclear talks with world powers this week but added that a higher-level meeting would probably be needed.

The Geneva talks, set to take place on Tuesday and Wednesday, will be the first such negotiations since President Hassan Rouhani, a reputed moderate, took office in August.

"I hope that we will be able to reach a roadmap by Wednesday but... it will probably be necessary to have a new ministerial meeting," Foreign Minister Mohammad Javad Zarif wrote on his Facebook page late on Sunday.

A first meeting between Zarif and his counterparts from the six powers took place last month on the sidelines of the United Nations General Assembly, which was accompanied by a landmark bilateral meeting between him and US Secretary of State John Kerry.

The Geneva negotiations will be between Iran's deputy foreign minister Abbas Araqchi and representatives of the P5+1 group made up of Britain, China, France, Russia and the United States plus Germany, who will be led by EU foreign policy chief Catherine Ashton.

After meeting Ashton in London on Sunday, Kerry said that the window for diplomacy with Iran was "cracking open".

But he also warned that Washington would remain wary during the negotiations as he spoke to the American Israel Public Affairs Committee summit in Washington via satellite from London.

"When President (Barack) Obama says that he will not allow a nuclear-armed Iran, he means what he says. I believe firmly that no deal is better than a bad deal," Kerry said.

Israel has repeatedly called on its US ally not to fall for "sweet talk" from the new Iranian president, insisting that actions not words are essential to ensure there is no possibility of Iran ever acquiring the capability to build an atomic bomb.

Israeli Intelligence Minister Yuval Steinitz called on Monday for the pressure of EU and US sanctions against Iran to be kept up, saying that was what was driving it to seek an agreement with the major powers.

"The Iranians are coming to dialogue... only because of the very severe economic pressure," Steinitz told reporters in Jerusalem.

Change of approach

Zarif will take part in the opening sessions in Geneva but Araqchi will lead the Iranian delegation during the talks.

The foreign minister wrote on his Facebook page, however, that "if necessary, I will also speak".

"We want to change the approach of the past six years which have given no results," he said.

Zarif has taken over as Iran's lead nuclear negotiator, but he has so far refused to be drawn on what Iran might offer in return for relief from EU and US sanctions, which have badly hit Iran's oil exports and its access to global banking.

"We will present our views, as agreed, in Geneva, not before," Zarif tweeted.

Araqchi, speaking to the state broadcaster on Sunday, said the "plan that will be presented by Zarif to the P5+1 countries during the opening session... has been prepared so that there can be no pretext to refuse it".

He did not give further details of the plan but said Iran would not accept any demand to hand over its stockpiles of enriched uranium.

"We will negotiate about the volume, levels and the methods of enrichment but shipping out the (enriched) material is a red line for Iran," Araqchi said.

Iran currently has 6,774 kilograms of low-enriched uranium, and nearly 186 kilograms of material enriched to 20 percent, as well as 187 kilograms of the 20 percent material converted to uranium oxide for use in fuel plates.

The 20 percent enriched uranium is the source of the greatest concern for the West and Israel, which fear Tehran could divert some of it for further enrichment towards the more than 90 percent level required for a nuclear weapon.

Iran insists that its nuclear programme is solely for peaceful purposes, and has defied repeated ultimatums from the UN Security Council to suspend all enrichment.

Israel minister calls for pressure on Iran to be kept up
Jerusalem (AFP) Oct 14, 2013 - The Israeli intelligence minister called on the major powers on Monday to maintain pressure on Iran, saying that was what was driving it to seek a deal in nuclear talks.

Yuval Steinitz, who is also minister for international relations, was speaking on the eve of revived negotiations on Tehran's controversial nuclear programme between Iranian officials and the P5+1 group of Britain, China, France, Russia and the United States, plus Germany.

"Iran needs agreement urgently," Steinitz told reporters in Jerusalem.

"The Iranian economy is in very bad shape... the dilemma will be crystal clear to them, that if they want to save their economy, they need to give up their nuclear project," he said.

"The Iranians are coming to dialogue... only because of the very severe economic pressure."

The new Iranian government of President Hassan Rouhani has pledged a fresh approach to the nuclear talks as it seeks relief from crippling EU and US sanctions, that have badly hit Iran's oil exports and access to global banking.

Steinitz insisted, however, that a "credible military threat would increase the chances" of reaching agreement in the nuclear talks.

He cited Iran's ally Syria as an example of the threat of force achieving disarmament, saying Damascus had agreed last month to destroy its chemical arsenal only because US military action looked imminent.

"I am confident that if we sat here one year ago, none of us, including myself, would dream or think that it's possible (President Bashar) al-Assad would sign an agreement to dismantle his chemical weapons, but also to dismantle production capacity to produce chemical weapons in the future."

But US President Barack Obama "came with a credible military threat, and suddenly there is a diplomatic breakthrough, and Syria did sign a clear commitment to dismantle all its chemical weapons... and production facilities," he said.

Israel has repeatedly threatened military action to prevent any chance of Iran developing a nuclear weapon and Prime Minister Benjamin Netanyahu told the UN General Assembly earlier this month that Israel was ready to do so unilaterally if necessary.