Iran and world powers will resume negotiations on its contested nuclear activities on July 2 after a round of talks in Vienna this week that Tehran said yielded some progress, but no breakthrough on the main sticking points.
The six countries - the United States, Russia, China, France, Britain and Germany - and Iran are striving to reach a comprehensive deal by the July 20 deadline that would curb Tehran's nuclear programme in exchange for a phased end to sanctions.
But Iranian Foreign Minister Mohammad Javad Zarif said major differences persisted after five more days of talks in the Austrian capital, and urged the six nations to "abandon excessive demands which will not be accepted by Iran".
A senior Chinese official said the two sides had agreed on a "textual framework" in Vienna this week but gave no details.
"The fact that (we came up) with this text is progress in procedural terms," a senior Chinese official, Wang Qun, told reporters after the talks.
The other side should abandon its excessive demands. Iran
will never accept such demands
Other diplomats told the Reuters news agency earlier in the week, however, that one of the most difficult issues in the talks, the number of centrifuges Tehran would be allowed to keep to enrich uranium under any deal, remained unresolved.
A spokesman for European Union foreign policy chief Catherine Ashton, who coordinates the talks, said only that the two sides had begun drafting the text of a deal at the talks in Vienna, their fifth round of negotiations so far this year.
"We have worked extremely hard all week to develop elements we can bring together when we meet for the next round in Vienna, beginning on July 2," Michael Mann said in a statement.
"We presented each other with a number of ideas on a range of issues, and we have begun the drafting process."
The sides are seeking a settlement that would limit Iran's nuclear programme, subject it to stricter UN inspections and lift sanctions impairing Iran's oil-based economy.
But with time running out if a risky extension of the talks past July 20 is to be averted, the two sides remain far apart over the permissible future scope of Iranian nuclear activity.
Iran 'fulfilled commitment'
The fifth round of talks came to an end as the UN International Atomic Energy Agency said in a report on Friday that Iran has reportedly fulfilled its commitment to eliminate virtually all of its most sensitive stockpile of enriched uranium gas under a landmark nuclear deal made with six world powers last year.
The IAEA report on the interim accord's implementation, which has a key role in ensuring that Iran lives up to its part of the November 24 agreement showed on Friday that Iran has met its pledge to curb its disputed atomic activities.
The confidential report was obtained by the Reuters shortly after it was issued to IAEA member states.
It said that since the six-month accord took effect on January 20, Iran had either diluted to a lower enrichment level or fed for conversion into a less proliferation-sensitive oxide form about 97 percent of its holding of uranium gas refined to a fissile concentration of 20 percent.
The enriched uranium stockpile has been of a particular concern for the West as the enrichment purity represents a relatively short step away from creating nuclear weapons.