VIENNA (AP) -- Iran and six world powers failed Saturday to meet their target date for cutting a nuclear deal but agreed to extend the talks until Nov. 24 in a bid to overcome stubborn differences over the size and capacity of activities by Tehran that could be used to make nuclear arms.
Months of exhausting negotiations were meant to culminate in an agreement by Sunday that would limit programs Iran says it needs to produce energy and for other peaceful purposes -- but which can also be used to make nuclear arms. In return, Tehran would have gotten progressive relief from all nuclear-related sanctions on its economy.
With both the U.S. and Tehran facing pressure from powerful skeptics at home, the two sides tried to put a good face what had been accomplished, while acknowledging that full agreement was a distance away.
We have made tangible process on some of the issues," said EU foreign policy chief Catherine Ashton, who coordinated the talks on behalf of the U.S. Russia, China, Britain, France and Germany. But she cautioned of "significant gaps on some core issues which will require more time and effort."
Iranian Foreign Minister Mohammad Javad Zarif read the same statement in Farsi.
U.S. Secretary of State John Kerry, who flew into Vienna a week ago to try and advance the talks, said stretching out the talks "is warranted by the progress we've made and the path forward we can envision," while a White House statement said that with the extension, there is a "credible prospect for a comprehensive deal."
But the extra time also means that both the U.S. and Tehran will increasingly be negotiating not only with each other but also those at home who have been vary of the current talks since they began early this year. Negotiators for both sides will have to thread a fine line between offering compromises needed to seal a deal while placating domestic factions whose opposition to concessions could scuttle the diplomatic process.
For President Barack Obama, that's powerful members of Congress.
Ed Royce, a Republican and chairman of the House Foreign Affairs Committee criticized the extension shortly after it was announced. "It looks like the Iranians won extra time with a good cop-bad cop routine," he said.
Lobbying against such sentiments, U.S. officials speaking to reporters after the extension was announced said any moves by Congress to move forward with new sanctions during the additional talks would likely derail the negotiations, divide the six powers and provoke Iran.
The officials said President Barack Obama continues to oppose new sanctions legislation before the talks expire and would veto such legislation. But if the talks ultimately fail, officials said, the Obama administration would support further sanctions against Iran.
Iran's Ya Lesarat weekly, meanwhile elucidated the fears of hard-liners in Tehran who see their country's atomic achievements as a source of national pride, writing that the U.S. aim is to "restrict Iran's nuclear program as much as possible."
U.S. officials spoke of progress on reducing the proliferation dangers from a reactor that would produce enough plutonium to arm several nuclear weapons if completed as planned. They also said headway was made on repurposing an underground site that Iran had used for uranium enrichment -- like plutonium a potential pathway to a nuclear bomb.
But the main dispute remains over uranium enrichment Up to last week, Iran, which insists it does not want nuclear arms, pushed to be allowed to expand its enrichment program over the next eight years to a level that would need about 190,000 current model centrifuges.
It now has about 20,000 centrifuges, with half of them operating. Iranian officials have recently signaled they are ready to freeze that number for now. But Kerry said Tuesday that Washington has made it "crystal clear" that even 10,000 are too many. Diplomats say Washington wants no more than 2,000.
Iran has received more than $6 billion of sanctions relief since late last year under an interim nuclear deal and the U.S. officials said that Tehran would get access to an additional $2.8 billion of frozen assets during the extended talks. But the officials, who demanded anonymity as a condition for briefing reporters, said that Washington would continue to emphasize to businesses around the world that Iran isn't open for business.
One of them warned that for those who evade or circumvent sanctions, "we will continue to come down on them like a ton of bricks."
Associated Press writers Josh Lederman in Washington and Nasser Karimi in Tehran contributed to this report.
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