The latest round of talks between Iran and world powers have concluded in Geneva, Switzerland, with Iran indicating a willingness to scale back uranium enrichment, as well as allowing for snap inspections of its nuclear sites as part of a new proposal to end a decade-long standoff with world powers.
Full details of Iran's proposals, presented during two days of negotiations in Geneva with six world powers, have not been made public.
Normally, the less negotiators leak news, the more it shows the seriousness of the negotiations and the possibility of reaching an agreement.
But, in a clear sign of hope, the two sides agreed to hold follow-up negotiations on November 7 and 8 in Geneva, a Western diplomat told Reuters news agency as the current two-day talks drew to a close.
"We hope that this is a beginning of a new phase in our relations," Iran's foreign minister, Mohammad Javad Zarif, told reporters on Wednesday.
After a six-month hiatus, Iran and the United States, Russia, China, France, Britain and Germany began negotiations in earnest on Tuesday to end a long impasse.
The White House said on Wednesday that the Iranian proposal showed "a level of seriousness and substance that we had not seen before".
Both sides sought to dampen expectations of any rapid deal at the meeting, the first since President Hassan Rouhani was elected in June pledging to scrap the politics of confrontation to ease Iran's international isolation.
After the first day of talks in Geneva, Iranian Deputy Foreign Minister Abbas Araqchi suggested Tehran was prepared to address long-standing calls for the UN nuclear watchdog to have wider and more intrusive inspection powers.
He also told the official IRNA news agency that measures related to its uranium enrichment were part of the Iranian proposal, but hinted the Islamic Republic was not inclined to make its concessions quickly.
Diplomats said other proposals Iranian envoys had made regarding eventual "confidence-building" steps included halting 20 percent enrichment and possibly converting at least some of existing 20 percent stockpiles to uranium oxide suitable for processing into reactor fuel.
"Neither of these issues are within the first step [of the Iranian proposal] but form part of our last steps," Araqchi said without elaborating, in comments reported on Wednesday.
'We need to keep talking'
Iran did not intend to renounce all enrichment "under any circumstances", the Russian state news agency RIA quoted an unidentified Iranian delegation source as saying.
Western officials have repeatedly said that Iran must suspend enriching uranium to 20 percent fissile purity, their main worry, before sanctions are eased.
"Are we there yet? No, but we need to keep talking," a Western diplomat said as talks resumed on Wednesday.
But Iran, diplomats said, has made much more concrete proposals than in the past, to the point that Tehran's negotiators were concerned about details being aired in public before they had had a chance to sell them back in Tehran.
Catherine Ashton, the European Union foreign policy chief, praised the talks as "substantive and forward-looking" in a statement she read on Wednesday evening. The White House also spoke positively about the meeting, saying Iran showed "a level of seriousness and substance that we have not seen before."
Zarif said in a post on Facebook that secrecy was working in the negotiators' favour.
"Normally, the less negotiators leak news, the more it shows the seriousness of the negotiations and the possibility of reaching an agreement," he said.