By PETER BAKER
WASHINGTON — The long-fractured relationship between the United States and Iran took a significant turn on Friday when President Obama and President Hassan Rouhani became the first leaders of their countries to speak since the Tehran hostage crisis more than three decades ago.
In a hurriedly arranged telephone call, Mr. Obama reached Mr. Rouhani as the Iranian leader was headed to the airport to leave New York after a whirlwind news media and diplomatic blitz. The two agreed to accelerate talks aimed at defusing the dispute over Iran’s nuclear program and afterward expressed optimism at the prospect of a rapprochement that would transform the Middle East.
“Resolving this issue, obviously, could also serve as a major step forward in a new relationship between the United States and the Islamic Republic of Iran, one based on mutual interests and mutual respect,” Mr. Obama, referring to Tehran’s nuclear program, told reporters at the White House after the 15-minute phone call. “It would also help facilitate a better relationship between Iran and the international community, as well as others in the region.”
A Twitter account in Mr. Rouhani’s name later stated, “In regards to nuclear issue, with political will, there is a way to rapidly solve the matter.” The account added that Mr. Rouhani had told Mr. Obama, “We’re hopeful about what we will see from” the United States and other major powers “in coming weeks and months.”
The conversation was the first between Iranian and American leaders since 1979 when President Jimmy Carter spoke by telephone with Shah Mohammed Reza Pahlavi shortly before the shah left the country, according to Iran experts. The Islamic Revolution that toppled the shah’s government led to the seizure of the American Embassy and a 444-day hostage crisis that have left the two countries at odds with each other ever since.
Although both Republican and Democratic presidents have reached out to Tehran in the interim, contact had been reserved to letters or lower-level officials.
The call came just days after Mr. Obama had hoped to encounter Mr. Rouhani at a luncheon at the United Nations and expected to shake hands. Mr. Rouhani skipped the luncheon and later indicated it was premature to meet Mr. Obama. But a meeting on Thursday between Secretary of State John Kerry and Foreign Minister Mohammad Javad Zarif of Iran was described as constructive and led Iranian officials to contact the White House on Friday to suggest the phone call, according to American officials.
A senior Obama administration official, who briefed reporters on the condition of anonymity because of diplomatic sensitivities, said the White House had expressed the president’s interest in meeting Mr. Rouhani to the Iranians this week but was surprised when they suggested the phone call. Mr. Obama placed the call from the Oval Office around 2:30 p.m., joined by aides and a translator.
He opened by congratulating Mr. Rouhani on his election in June and noted the history of mistrust between the two nations, but also what he called the constructive statements Mr. Rouhani had made during his stay in New York, according to the official. The bulk of the call focused on the nuclear dispute, and Mr. Obama repeated that he respected Iran’s right to develop civilian nuclear energy, but insisted on concessions to prevent development of weapons.
Mr. Obama also raised the cases of three Americans in Iran, one missing and two others detained. In a lighter moment, he apologized for New York traffic.
The call ended on a polite note, according to the official and Mr. Rouhani’s Twitter account.
“Have a nice day,” Mr. Rouhani said in English.
“Thank you,” Mr. Obama replied, and then tried a Persian farewell. “Khodahafez.”
By talking on the phone instead of in person, Mr. Rouhani avoided a politically problematic photo of himself with Mr. Obama, which could have inflamed hard-liners in Iran who were already wary of his outreach to the United States. As it was, conservative elements in Tehran tried to reinterpret his statements acknowledging the Holocaust while he was in New York.
The state news channel, the Islamic Republic of Iran News Network, had not mentioned the phone call with Mr. Obama as of midnight Friday after word of it broke, and the original messages on Mr. Rouhani’s Twitter account were deleted and replaced with more anodyne comments. But Mr. Rouhani’s office announced the call in a statement carried by the Iranian state news agency.
“This voice contact has for now replaced the actual shaking of hands, but this is clearly the start of a process that could in the future lead to a face-to-face meeting between both leaders,” said Amir Mohebbian, a political adviser close to Iran’s supreme leader, Ayatollah Ali Khamenei.
Abbas Milani, an Iranian scholar at Stanford University, said Mr. Rouhani wanted to avoid looking as if he was making concessions. “The U.S. and the West have wisely decided to allow the regime to make its claims of victory at home, so long as they play earnest ball in meetings abroad,” Mr. Milani said. A call to a leader on the way to the airport may not be normal protocol, he added, but “in this case it was adroit policy for both sides.”
American advocates of closer relations between the two countries were optimistic. “The phone call wasn’t just history,” said Joseph Cirincione, president of the Ploughshares Fund, an arms control group, who attended a dinner with Mr. Rouhani in New York. “It helped fundamentally change the course of Iranian-U.S. relations. We’re on a very different trajectory than we were even at the beginning of the week.”
But others expressed caution, arguing that Iran was reaching out only because of the sanctions that have strangled its economy.
“The economic pain now is sufficient to oblige a telephone call, though not a face-to-face meeting,” said Reuel Marc Gerecht, a senior fellow at the Foundation for Defense of Democracies, which supports stronger sanctions against Iran. “We will see whether the pain is sufficient for the Iranians to shut the heavy-water plant at Arak and reverse Iran’s path to a rapid breakout capacity with enriched uranium.”
Representative Eric Cantor of Virginia, the Republican majority leader, criticized Mr. Obama for not pressing Iran to halt what he said was its support for terrorism and for Syria’s government. “It is particularly unfortunate that President Obama would recognize the Iranian people’s right to nuclear energy but not stand up for their right to freedom, human rights or democracy,” he said.
In announcing the call with Mr. Rouhani, Mr. Obama said that only “meaningful, transparent and verifiable actions” on the nuclear program could “bring relief” from sanctions.
“A path to a meaningful agreement will be difficult, and at this point, both sides have significant concerns that will have to be overcome,” he said. “But I believe we’ve got a responsibility to pursue diplomacy, and that we have a unique opportunity to make progress with the new leadership in Tehran.”
Recognizing the delicacy of the outreach effort, Mr. Obama made a point of trying to reassure Israel that he would not jeopardize an ally’s security. “Throughout this process, we’ll stay in close touch with our friends and allies in the region, including Israel,” he said.
Prime Minister Benjamin Netanyahu of Israel is scheduled to visit Mr. Obama at the White House on Monday.
Before leaving New York, Mr. Rouhani said his government would present a plan in three weeks on how to resolve the nuclear standoff. “I expect this trip will be the first step and the beginning of constructive relations with countries of the world,” he said at a news conference.
He went on to say that he hoped the visit would also improve relations “between two great nations, Iran and the United States,” adding that the trip had exceeded his expectations.
Mr. Rouhani and his aides have been on an extraordinarily energetic campaign to prove that they are moderate and reasonable partners and to draw a stark contrast with his predecessor, Mahmoud Ahmadinejad. But Mr. Rouhani has yet to propose anything concrete to suggest how different the Iranians really are in their approach. The first glimpse of that is due to come on Oct. 15 and 16, when Iran plans to present its own road map in Geneva.
Mr. Rouhani emphasized that his government had the authority and the will to reach a nuclear settlement within what he called “a short period of time.” But he was visibly irritated when asked whether his diplomatic blitz was merely designed to buy time with his Western interlocutors.
“We have never chosen deceit as a path,” he said. “We have never chosen secrecy.”