Iran says international negotiators have welcomed a proposal its foreign minister made at the start of a fresh round of nuclear talks in Geneva Tuesday morning.
Iranian Deputy Foreign Minister Abbas Araqchi said the six world powers had "welcomed" Tehran's proposals and the details would be discussed later in the day. Negotiations led by foreign ministry political directors resumed in the afternoon.
Western officials said the hour-long PowerPoint presentation by Foreign Minister Mohammad Javad Zarif and his team was for the first time delivered in English, underlining a new mood in the often-tense nuclear discussions.
Details of the Iranian plan were not immediately available.
The United States, Russia, China, France, Britain and Germany want Iran to prove it is not developing nuclear weapons, while Iran is seeking relief from international sanctions levied in response to its refusal to halt enrichment activities.
Michael Mann, spokesman for European Union foreign policy chief Catherine Ashton, said the so-called P5+1 have had their own proposal on the table since an earlier round of talks.
"It is the Iranian side who we believe to be in breach of their international obligations. There are Security Council resolutions and IAEA Board of Governors resolutions about the Iranian nuclear program, so the way it is is that the confidence-building measure we have on the table is for the Iranians to take. So the ball remains in their court."
Ashton said she had "cautious optimism" going into the two days of talks in Geneva.
Iranian President Hassan Rouhani has promised to lead a diplomatic effort to get the sanctions eased, but officials from the P5+1 group of nations have expressed the need for Iran to prove its sincerity through concrete steps before that will happen.
Israeli Prime Minister Benjamin Netanyahu's security cabinet cautioned the world powers against making any partial deal with Iran, saying they must reject any agreement "that leaves Iran with the capability to develop nuclear weapons."
In Washington, a bipartisan group of leading U.S. senators said it is open to suspending the implementation of new sanctions on Iran but only if Tehran takes significant steps to slow its nuclear program.
But Iran is not expected to offer to suspend enrichment during the talks.
In previous rounds of 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.