Iranian Foreign Minister Javad Zarif (right) and the head of Iranian Atomic Energy Organisation Ali Akbar Salehi stand with other members of their delegation after a meeting with US Secretary of State John Kerry at the Beau Rivage Palace Hotel in Lausanne yesterday. Photo: Reuters

Negotiations between six world powers and Iran over its nuclear programme have been “tough and very serious” and the next few days will show whether Tehran is ready to make the necessary hard decisions, a senior US official said yesterday.

Iranian President Hassan Rouhani’s move to reach out to the leaders of the six powers on Thursday is “hopefully a sign that Iran is ready to make some of the tough decisions,” the senior State Department official added on condition of anonymity.

The official said that other foreign ministers from the six-power group, which includes Britain, China, France, Germany, Russia as well as the United States, will arrive in the coming days to join the talks in Lausanne, Switzerland ahead of an end-March deadline for a political framework agreement.

Tehran and the powers are struggling to hammer out a political framework accord by the end of this month that would lay the foundations for a full settlement by June 30.

Under a final accord, Tehran would halt sensitive nuclear work for at least a decade and in exchange, international financial and oil and some UN sanctions on Iran would be lifted. This would aim to end Iran’s 12-year nuclear standoff with the West and reduce the risk of war in the Middle East.

While all sides agree they are moving closer to a deal, there are major disagreements.

Tehran insists on the freedom to continue research on advanced centrifuges, machines that purify uranium for use in nuclear power plants or, if very highly enriched, in weapons, at the underground Fordow site, and immediate lifting of all UN sanctions and the most severe US and European Union sanctions.

The important thing is the content not the deadline

“There has been massive progress on all the issues,” a senior Iranian official said. “There are still disputes over two issues – research and development, and UN sanctions.”

A Western official close to the talks confirmed that centrifuge research and enrichment in general remained the most difficult unresolved issue. The foreign minister of France, which negotiators say has demanded the most stringent limits on future Iranian nuclear activity if it is to support a deal, made clear there was more work to do while playing down the importance of the deadline.

“The important thing is the content not the deadline,” Foreign Minister Laurent Fabius told reporters at the UN in New York. “There has been some progress, but there are things which are not yet solved.”

The United States and European partners are reluctant to allow Iran to operate centrifuges at the Fordow site, Western officials said, adding that the issue was unresolved.