Obama calls Rouhani as Iran optimism precedes nuclear talks

President Barack Obama phoned his Iranian counterpart, Hassan Rouhani, to discuss the outlook for nuclear talks, as a thaw between the countries gained momentum with the first contact between their leaders in decades.

The call today took place as Rouhani was en route to the airport in New York after addressing the United Nations earlier this week, Iran's official IRNA news agency reported. Afterward, Obama told reporters at the White House that there's a "unique opportunity" to reach an agreement, though he said he's "mindful" of the obstacles.

Iran's pursuit of atomic technology has led Obama and his allies in Europe to tighten economic sanctions, and the US and Israel to threaten military action, to prevent the Islamic republic from obtaining nuclear weapons. Iran denies that it's seeking to do so. Rouhani took office last month after winning election on a pledge to end Iran's global isolation and ease the trade curbs, and at the UN this week he has repeatedly said his government is ready for a deal.

The nuclear talks stalled in April, when Rouhani's predecessor, Mahmoud Ahmadinejad, was still in power. They got under way again in New York late yesterday when US Secretary of State John Kerry and his counterparts from five other world powers met with Iranian Foreign Minister Mohammad Javad Zarif, who proposed a goal of implementing an agreement within a year.

It was the highest-level US-Iranian encounter since the Islamic revolution of 1979. The participants agreed to "jump-start the process so we could move forward with a view to agree first on the parameters of the endgame," Zarif said afterward.

Diplomats and analysts have warned that the real test of Rouhani's commitment to an accord will start when detailed negotiations resume in Geneva on October 15. Concerns about Iran's nuclear program remain, and "one meeting and a change in tone, which was welcome, doesn't answer those questions yet," Kerry said on Friday.