Iran and world powers have ended two days of talks aimed at breaking a decade-old deadlock over the country's disputed controversial nuclear programme.
The two sides held a tense day of negotiation in the Kazakh city of Almaty on Friday that ended with no breakthrough.
Al Jazeera's Robin Forestier-Walker, reporting from Almaty on Saturday, said that he had got a sense of frustration from negotiators.
"It did not look like the two sides were seeing eye-to-eye," he said. "As long as the two sides can keep talking, there may be no strike by Israel. That is the best that both sides can hope for."
As the talks got underway on Friday, the six nations - the US, Russia, China, France, Britain and Germany - sought a concrete response from Iran to their February offer to ease sanctions if it stops its most sensitive nuclear work.
Iranian negotiators said they had outlined their own "specific" proposals, but a Western diplomat said they had still not responded clearly to the initiative from the big powers.
The dissonant views suggested the two sides had not narrowed differences that have plague a decade of on-off talks.
Iran's deputy negotiator, Ali Bagheri, did not say whether the offer was acceptable, but said his side had made "specific proposals .. for the start of a new round of cooperation".
"Naturally, the talks will continue," he said after talks paused for Iranian negotiators to join Friday prayers at Almaty's main mosque.
The dispute centres on Iranian efforts to enrich uranium, which world powers suspect are part of a covert drive to achieve atom bomb capability.
The UN Security Council has demanded that Iran stop the process in several resolutions since 2006.
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Iran argues it has the right to enrich uranium for peaceful purposes under international law and denies its nuclear work has military aims. It has refused to change course unless the big powers recognise its right to enrichment and lift sanctions.
The stakes are high because Israel, widely assumed to be the Middle East's only nuclear-armed power, has threatened to bomb the Islamic Republic's atomic sites if diplomacy fails.
Chances for a quick breakthrough are seen as scant, with Iran not expected to make any major decisions on nuclear policy until after its presidential election in June.
Western diplomats are hoping at least for serious discussion of their February proposal, under which Iran would have to close a nuclear facility and ship some enriched uranium stockpiles abroad in return for modest relief on sanctions on Iranian petrochemicals and trade in gold and other precious metals.
For years Iran has resisted ever-harsher sanctions and pressure to retreat from a nuclear programme that enjoys broad support among its fractious political leadership.
Iran's chief negotiator, Saeed Jalili, said in a speech at Almaty University on the eve of the latest talks that their success hinged on "acceptance of the rights of Iran, particularly the right to enrichment."
The six nations, however, say this right only applies when nuclear work is carried out under sufficient oversight by UN inspectors, something Iran has refused to grant.
For now, Iran may play for time, trying to keep diplomacy on track to avert new sanctions before the June election.
Tehran's conversion of some its higher-grade uranium stockpile to nuclear reactor fuel may have bought time for diplomatic efforts to resolve the dispute peacefully.
But if talks fail to produce sufficient progress, Western governments are likely to impose yet more economic penalties, with the double aim of pressuring Iran while seeking to persuade Israel to hold back from any military action.
Binyamin Netanyahu, the Israeli prime minister, told visiting US senators on Thursday that Iran's nuclear work must be stopped.
"We cannot allow a situation in which a regime that calls for our annihilation has the weapons of annihilation," he said.