Iran and six world powers appeared closer yesterday towards clinching an elusive interim deal under which Tehran would curb its contested nuclear programme, with diplomats saying a major sticking point may have been overcome.

A compromise deal over Iran’s insistence that its “right” to enrich uranium be internationally recognised has been proposed, they said, possibly opening the way to a breakthrough in intensive negotiations that began in Geneva on Wednesday.

The US and other Western powers say there is no such thing as a right to enrich – a process that can yield both electricity and nuclear bombs – but Iran views it as a matter of national sovereignty and crucial to any deal that would resolve a decade-old standoff over its nuclear intentions.

The Islamic Republic also wants relief from economic sanctions in return for any nuclear concessions that could allay the West’s suspicions that its nuclear fuel-making programme has military rather than its stated civilian goals.

In another sign the sides could be edging towards an agreement, Western diplomats said US Secretary of State John Kerry was tentatively planning to join the high-stakes talks in Switzerland although he has yet to confirm his plans.

Russian Foreign Minister Sergei Lavrov arrived in Geneva yesterday evening and planned to participate, spokesman Maria Zakharova said. “I can confirm that we are staying on Friday and Saturday. That is the plan,” she told reporters. Zakharova did not rule out Lavrov staying even longer.

Foreign ministers from the six nations negotiating with Iran – the UK, Russia, China, France, Britain and Germany – waded into the previous talks from November 7-9 and came close to winning concessions from Iran, which they count on to reduce the risk of it honing a nuclear weapons capability.

In the days running up to the talks, policymakers from the six powers said an interim accord on confidence-building steps could be within reach to start a cautious process of detente with Iran and douse the spectre of a wider Middle East war.

Under discussion is Iranian suspension of some sensitive nuclear activities, above all medium-level uranium enrichment, in exchange for sanctions relief.

That could involve releasing some Iranian funds frozen in foreign bank accounts and allowing trade in precious metals, petrochemicals and aircraft parts.

The US might also agree to relax pressure on other countries not to buy Iranian oil. Tehran has made clear it wants more significant gestures diluting the stifling superstructure of sanctions blocking its lifeblood oil exports and use of the international banking and financial system.

Diplomacy on Tehran’s nuclear aspirations has revived remarkably since the election of Hassan Rouhani, a relative moderate, as president in June on promises of winning sanctions relief and diminishing Iran’s international isolation.

But the sides have struggled to wrap up a deal, bogged down in politically vexed details and still hampered by a long legacy of mutual mistrust.

Diplomats said new, compromise language of a deal being discussed did not explicitly recognise a right to produce nuclear fuel by any country. “If you speak about the right to a peaceful nuclear programme that’s open to interpretation,” a diplomat told Reuters without elaborating.

No other details were available, but Iranian Foreign Minister Mohammad Javad Zarif, Tehran’s chief negotiator, said earlier in the day that significant headway had been made.

Meanwhile, Israel continued its public campaign of criticising the offer of sanctions rollbacks for Iran, voicing its conviction that all it would achieve would be more time for Iran to master nuclear technology and amass potential bomb fuel.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.