Iran nuclear crisis: 'Useful' talks in Kazakhstan
World powers have been holding talks with Iran over its controversial nuclear programme.
A Western official said Tuesday's talks in the Kazakh city of Almaty had been "useful" and the sides would meet again on Wednesday.
The discussions are the first since talks in July 2012 ended without a breakthrough.
Negotiators from Iran are meeting counterparts from the US, UK, France, China, Russia and Germany - the P5+1.
International powers suspect Iran of seeking to develop nuclear weapons - a charge Iran strongly denies.
Iran insists its purposes are purely civilian, asserting it needs enriched uranium to make medical isotopes.
Since 2010, Iran has been enriching uranium to a level of 20%, an important technological step towards being able to produce more highly enriched weapons-grade material.
Each new round of the Iranian nuclear talks follows almost exactly the same choreography as the round before. Negotiators find themselves part of a de facto troupe on world tour - giving the same performance in different cities. These talks in Almaty follow previous rounds held in Geneva, Istanbul, Baghdad, and Moscow.
During the opening three-hour session, Baroness Catherine Ashton - the lead negotiator for the world powers - presented what's described as a revised offer to Iran. The proposal is thought to repeat an earlier demand to stop uranium enrichment and to shut down an underground enrichment facility near the city of Qom.
Iranian officials say that the Islamic Republic will listen to what the world powers have to say before deciding whether to reply with a counter-offer.
The two sides have until Thursday to see if they can break precedent and reach a lasting agreement.
Iran has repeatedly rejected Western calls to stop enriching uranium, insisting it is an inalienable right.
Western negotiators at the meeting are expected to offer Iran incentives to compromise.
"The offer addresses the international concern on the exclusively peaceful nature of the Iranian nuclear program, but it is also responsive to Iranian ideas,'' said EU spokesman Michael Mann.
"We've put some proposals forward which will hopefully allow Iran to show some flexibility.''
The proposals might involve easing some of the sanctions which have been imposed on Iran, in return for shutting its Fordo uranium enrichment plant, reports say.
Several rounds of sanctions have squeezed Iran's economy, with oil revenue slashed, a currency that has nosedived in value, and growing unemployment.
Iran's Press TV said Iran would also offer "a new comprehensive package of proposals", without giving details.'Window still open'
The talks are taking place against a background of Israeli warnings that it will stop Iran's programme militarily if other means fail.
Speaking in London on Monday, new US Secretary of State John Kerry said time for a diplomatic solution was running short.
"The window for a diplomatic solution simply cannot by definition remain open forever. But it is open today. It is open now," he said.
"There is still time but there is only time if Iran makes the decision to come to the table and negotiate in good faith."
Russian Deputy Foreign Minister Sergei Ryabkov told reporters in Almaty "no more time should be lost".
"One gets the impression that on the whole there is not too much readiness or desire to agree. This should be overcome," Interfax news agency quoted him as saying.
There has been little sign of the atmosphere easing. This month, Iran said it had found major new uranium deposits and was planning to expand its nuclear power programme.
Iran said the find - which has not been independently confirmed - would treble the size of known uranium deposits.
Only 10 days earlier, Iran announced an upgrade to its Natanz nuclear plant centrifuges - believed to be able to enrich uranium two or three times faster than the old equipment.
A report by the International Atomic Energy Agency (IAEA) last week said it could not yet "exclude the existence of possible military dimensions to Iran's nuclear programme".