Diplomats say they are tackling an entrenched uranium-enrichment standoff, as talks resume on Iran's disputed nuclear activities, the New York Times reports.
The focus emerged as Iran and six other countries prepared for new negotiations in Vienna over potential long-term limits on Tehran's atomic efforts, which Western powers see as cover for development of a nuclear-arms capability. The Middle Eastern nation denies any intention to refine uranium into nuclear-bomb fuel, and has raised the possibility of expanding its current fleet of 19,000 enrichment centrifuges to include 50,000 or more of the machines.
The United States, though, is urging Iran to cut its existing enrichment capacity so it would need more than 12 months to refine enough uranium for a bomb. Robert Einhorn, who stepped down in 2013 as U.S. State Department special adviser for nonproliferation and arms control, last week wrote that more than "a few thousand first-generation [Iranian] centrifuges" would be unacceptable.
Past months of negotiations have focused largely on less divisive issues, resulting partly in a tentative offer by Iran to modify its Arak heavy-water reactor to generate less weapon-usable plutonium upon activation.
Speaking on Monday, Russian Foreign Minister Sergei Ryabkov said "Arak and transparency [appear] riper than all other items on the agenda for getting primary results ... by Friday," ITAR-Tass reported.
Information on Iran's past atomic activities may emerge as a sticking point, Western envoys told Reuters for a Tuesday report. A Monday meeting between Tehran and the U.N. nuclear watchdog reportedly did not yield substantial traction.
Iranian Foreign Minister Mohammad Javad Zarif is expected to meet late on Tuesday with European Union foreign policy chief Catherine Ashton, who is representing the six other negotiating governments, the Los Angeles Times reported. Three days of discussions are slated to begin on Wednesday, with delegates from Iran as well as China, France, Germany, Russia, the United Kingdom and the United States.