Iran's foreign minister on Tuesday met with top world diplomats to outline technical aspects of a proposal to end a decade-long standoff with the international community over Iran's nuclear program.
Details of the closed-door Geneva meeting were not disclosed. But Iranian Deputy Foreign Minister Abbas Araqchi later said the six world powers "welcomed" Tehran's proposals. A senior U.S. State Department official was later quoted as saying the talks had been "detailed" and "useful."
Officials also noted the hourlong PowerPoint presentation by Foreign Minister Mohammad Javad Zarif was delivered in English, underlining a new mood in the international standoff. The so-called P5+1 talks are set to resume Wednesday.
The United States, Russia, China, France, Britain and Germany want Iran to prove it is not developing nuclear weapons, while Tehran is seeking relief from international sanctions aimed at forcing it to halt uranium enrichment activities.
The Geneva talks, the first since relative moderate Hassan Rouhani was elected Iran's president in June, is widely seen as the best chance for years to defuse a stand-off over Iran's nuclear ambitions.
Mr. Rouhani has promised to lead a diplomatic effort to get the economic sanctions eased, but P5+1 officials have said Iran must prove its sincerity through concrete steps before that will happen.
In Washington, a bipartisan group of leading U.S. senators said it is open to suspending the implementation of new sanctions, but only if Tehran takes significant steps to slow its nuclear program.
In previous negotiations, world powers called for Iran to give up its existing stockpile of uranium enriched to 20 percent purity and send it abroad. Uranium of that purity is a short technical step away from being converted to weapons-grade material.