Obama and Rouhani speak by phone

US president Barack Obama and new Iranian president Hassan Rouhani held a historic phone call on Friday, in the highest level conversation between the estranged nations in more than three decades.

Speaking to reporters at the White House, Mr Obama said both men had directed their teams to work expeditiously toward an agreement on Iran’s nuclear program. He said this was a unique opportunity to make progress with Tehran over an issue that has isolated it from the West.

“While there will surely be important obstacles to moving forward and success is by no means guaranteed, I believe we can reach a comprehensive solution,” Obama said.

Mr Rouhani, in a Twitter account believed to be genuine, said that in the conversation he told Mr Obama “Have a Nice Day!” and Mr Obama responded with “Thank you. Khodahafez (goodbye).” He added that the two men “expressed their mutual political will to rapidly solve the nuclear issue.”

The telephone call, the first between the heads of government of the two nations since the 1979 Islamic Revolution, came while Mr Rouhani was heading to the airport after his first visit to the United Nations general assembly, according to a statement on Rouhani's official website.

Secretary of state John Kerry and Iranian foreign minister Mohammad Javad Zarif have been asked to follow up on the Obama-Rouhani conversation, the statement added.

As president, Mr Rouhani is the head of the government but has limited powers. Supreme leader Ayatollah Ali Khamenei is the ultimate authority in Iran with final say on domestic and foreign policy, though Mr Rouhani says he has been given full authority to negotiate on the nuclear issue.

Mr Rouhani was on a charm offensive during his week in New York, repeatedly stressing Iran’s desire for normal relations with Western powers and denying it wanted a nuclear arsenal, while urging an end to sanctions that are crippling its economy.

In his speech to the 193-nation UN general assembly on Tuesday, Mr Obama cautiously embraced Mr Rouhani’s gestures as the basis for a possible nuclear deal and challenged him to demonstrate his sincerity.

However, the failure to orchestrate a handshake between the two leaders that day, apparently because of Mr Rouhani’s concerns about a backlash from hardliners at home - and perhaps Mr Obama’s concerns about the possibility of a failed overture - seemed to underscore how hard it may be to make diplomatic progress.

Mr Rouhani, who took office last month, told a news conference earlier today he hoped talks with the United States and five other major powers "will yield, in a short period of time, tangible results," on a nuclear deal. But he was less specific than he had been on Tuesday about the time scale.

He said Iran would bring a plan to resolve the decade-long dispute over Tehran’s nuclear program, which Western powers and their allies suspect is aimed at developing an atomic weapons capability, to an October meeting with the six powers in Geneva.

He offered no details about that plan, but emphasized that Tehran’s nuclear ambitions are entirely peaceful.

Reuters