Iranian president writes to Western leaders as nuclear negotiators come close to deadline

Iran's President Hassan Rouhani sent a letter to the leaders of the P5+1 group, including US President Barack Obama, as negotiations contuned in Switzerland over a possible agreement aimed at preventing Iran from building an atomic bomb

The content of the letters was not known, but Rouhani also phoned the leaders of Russia, China, Britain and France, his office said.

"We are acting in the national and international interest and we should not lose this exceptional opportunity," he reportedly told British Prime Minister David Cameron by phone, the presidency said.

"Hope was expressed for success at the new round of talks in Lausanne," the Kremlin said after Rouhani spoke to President Vladimir Putin, while noting with "satisfaction" the progress made.

Francois Hollande, "insisting on Iran's legitimate right to use peaceful nuclear power, insisted on the need to work toward a lasting, robust and verifiable agreement," the French presidency said. Iran wants all sanctions lifted

Highlighting the difficulties of talks that resumed in Switzerland yesterday between US Secretary of State John Kerry and his Iranian counterpart, Rouhani also said Iran wanted all sanctions lifted. "The peaceful character of the nuclear activities and the necessity to annul all the unjust sanctions can lead us to a final deal," Rouhani's office quoted him as telling Cameron.

However, the six nations negotiating with Iran - the United States, China, Russia, Britain, France and Germany - are insisting that sanctions would only be suspended, not lifted, to enable them to be quickly put back in place if Tehran violates the deal.

On Thursday, the US Senate voted unanimously for a non-binding measure to impose new sanctions on Iran should it violate terms of any nuclear deal reached.

Kerry held four-hour-long talks in Lausanne with Iranian Foreign Minister Mohammad Javad Zarif aimed at agreeing the outline of a nuclear deal by 31 March. "It's going well, we're working, we're meeting," Kerry said, pursued by reporters as he walked through the streets of Lausanne.