Senior representatives of Iran's new government have begun a potentially decisive round of nuclear talks with the United Nations contact group in Geneva.
European Union foreign policy chief Catherine Ashton met with Iranian Foreign Minister Javad Zarif on Wednesday.
Earlier, in Tehran, Iran's supreme leader said his country would not retreat on what he called the country's nuclear rights during negotiations with the six world powers. Ayatollah Ali Khameni said he set "red lines" for his negotiators, but also that Iran wants to be friendly with all nations, including the United States.
The five permanent members of the U.N. Security Council, along with Germany, want an interim agreement that calls for Iran to stop some of its enrichment activity and accept more inspections in return for limited sanctions relief.
Michael Mann, spokesman for Ashton, told VOA that while it is hard to predict the outcome, it is clear the talks are serious.
"I think the fact that we've come back to Geneva so soon after -- it was just 10 days after the last round -- shows how serious the negotiations are."
Both sides have expressed hope that a deal can be worked out to end the decade-long standoff.
Iranian Foreign Minister Javad Zarif said in a video posted on YouTube that there is "every possibility" of coming to an agreement.
British Prime Minister David Cameron's office said he and Iranian President Hassan Rouhani agreed in a telephone call Tuesday that "significant progress" was made in the last round of talks earlier this month.
The statement said Mr. Cameron also stressed the need for Iran to address the concerns of the international community, which has called for assurances that Iran is not trying to develop nuclear weapons.
Iran has repeatedly denied those accusations, saying its nuclear activity is solely for peaceful purposes.