(CNN) -- National Security Adviser Susan Rice on Friday described the first phone call between an American president and his Iranian counterpart in more than three decades as "cordial" and "constructive."
Rice told CNN's Fareed Zakaria that the Iranian delegation approached the Obama administration about a phone call between President Barack Obama and Iranian President Hassan Rouhani.
The request came after indicating earlier in the week that a direct meeting at the UN General Assembly would not be possible due to Iran's internal political reality.
"Today, somewhat surprisingly, we were contacted by them to say that President Rouhani would like to speak to President Obama on the telephone on his way out of town, and we were able to make that call come together and it was a constructive conversation," Rice said.
The full interview will air on "Fareed Zakaria GPS" Sunday at 10 a.m and 1 p.m. ET.
According to Rice, Friday's call lasted about 15 minutes. "Of course, with translation, it was a brief call, but sufficient to convey messages from both sides," she said.
"Obviously when you have two leaders from two countries that have not communicated at that level for almost 35 years, it's something of a ground-breaking event. But they both conveyed their commitment to try and explore in a constructive manner the diplomatic path," Rice said.
Rice reiterated that a nuclear weapon in Iran is unacceptable to Obama. For his part, Rouhani has said Iran has no interest in ever obtaining a nuclear weapon, although that assertion has been met with some skepticism.
Rice cited a variety of factors that led to the potential shift in U.S.-Iranian relations, including international pressure and sanctions on Iran as well as Rouhani's election, a moderate replacing anti-America hardliner Mahmoud Ahmadinejad.
"There is an opportunity now to test the proposition of that diplomatic settlement," Rice said.