Nuclear talks towards a lasting agreement between Iran and six powers appeared to make modest progress on a second day today, with Washington saying the negotiations were "constructive and useful".
Iranian state media said both sides were close to agreeing a framework agreement on how negotiations would proceed in future rounds over the coming months in what promises to be a lengthy process.
US State Department spokeswoman Marie Harf said that the Vienna talks between Iran and the United States, Russia, China, Britain, France and Germany had been "constructive and useful".
Negotiators discussed "both process and substance," she said.
Speaking to reporters, Harf declined to comment further, saying only that the talks would continue for a third day in the Austrian capital tomorrow.
Iranian Foreign Minister Mohammad Javad Zarif and EU foreign policy chief Catherine Ashton, the powers' chief negotiator, were expected to hold a closing news conference tomorrow morning.
The parties hope to create a lasting accord out of an landmark interim deal struck in November, under which Iran agreed to freeze certain nuclear activities for six months.
In exchange, the Western governments offered minor relief from a range of punishing sanctions that have cost Iran billions of dollars in lost oil revenues, as well as a promise of no new sanctions.
The six-month deal expires on July 20 but can be extended, with the parties aiming to conclude negotiations and implement the final "comprehensive" deal by November.
Zarif had said late Tuesday that the talks had "started on the right track".
"We have a shared objective, and that is for Iran to have a nuclear programme that is exclusively peaceful," he said.
He said a deal was "totally achievable" but would take more than "one or two sittings" and would require "some innovation and some forward thinking".
Others have been considerably more circumspect about the prospects for a deal that satisfies hardliners on both sides, as well as other countries such as Israel and Sunni monarchies in the Gulf.
Iran's supreme leader Ayatollah Ali Khamenei, who retains the final say on all matters, said on Monday that this effort would "go nowhere" but that he was not against trying.
