LONDON — Iran has accepted an invitation to join talks with the United States and Russia this week on a possible political resolution to the Syrian civil war, state news media reported on Wednesday.
The talks would be Secretary of State John Kerry's first formal negotiations with Tehran on issues beyond the nuclear accord reached in July.
The Iranian foreign minister, Mohammad Javad Zarif, and his Russian counterpart, Sergey V. Lavrov, discussed the talks, which will be held in Vienna, in phone conversations on Tuesday evening and Wednesday morning, the semiofficial ISNA agency quoted a Foreign Ministry spokeswoman, Marziyeh Afkham, as saying.
Russia has urged the inclusion of Iran, the only other major power giving military support to President Bashar Assad, and top U.S. officials have recently acknowledged that no serious discussion of a possible political succession plan in Syria could occur unless Tehran were involved.
France24 quoted Antony J. Blinken, the deputy secretary of state, who was in Paris in preparation for Friday's talks, as saying he hoped Iran could play "a positive role in supporting a political transition in Syria."
Kerry leaves for Vienna on Wednesday.
The U.S. position — denunciation of Iran's support for Assad's forces and for terrorist groups like Hezbollah — has until now precluded any support for Iran's participation in the talks. Along with Russia and the United States, Britain, France, Germany, Egypt, Jordan, Qatar, Saudi Arabia, Turkey and the United Arab Emirates are participating in this week's talks.
The change in the U.S. position was signaled on Tuesday in a State Department news conference in Washington.
Ayatollah Ali Khamenei, Iran's supreme leader, had ruled out bilateral negotiations with the United States after the nuclear accord, which he tepidly endorsed.
"It's very important because it shows that, following the nuclear agreement, Iran is now ready to cooperate on crisis management in the Middle East," Seyed Hossein Mousavian, a former Iranian diplomat and nuclear negotiator who now teaches at Princeton, said in a phone interview. "I'm not surprised, because the leader had said that if the deal were done fairly, with face-saving for all parties, Iran would agree to next steps on other issues. This is a big step forward."
Mousavian added: "There are, practically speaking, two coalitions: one established in 2011 by the United States, with its allies like Saudi Arabia, Qatar, Turkey, and the other coalition, established recently, by Russia, Iran, Iraq, Syria and Hezbollah." A resolution of the Syria crisis is impossible, he said, unless "all major regional powers and international powers agree to sit down together."
Michael Axworthy, a historian of Iran at the University of Exeter and a former British diplomat, said of the Iranians' participation in the talks: "It is quite significant. It's new that they've come along, but it's also new that the other countries involved have contemplated working with them."
He added: "In the aftermath of the nuclear deal, it was important for Khamenei to signal to his supporters that this was not an unraveling of Iran's hard-line position on the U.S. and Israel. Now that he's done that, it becomes possible to take further steps."
Russia's intervention in the conflict, with the launch of airstrikes last month against rebel forces that are fighting Assad, may also have changed Tehran's political calculus, Axworthy said. In the long run, he said, "they don't trust the Russians any more than they trust the U.S."
Blinken, in his interview with France24, reaffirmed the U.S. view that Russia's intervention has not significantly changed the situation. "They cannot win in Syria," he said. "They can perhaps prevent Assad from losing, but they cannot win. There is a recognition on all sides that there is no military solution in Syria. That is a recognition that is now growing on the Russians."
The last round of talks in Vienna ended last Friday without a resolution, although Kerry and Lavrov emphasized common ground: their shared fight against the Islamic State and other violent extremist groups, and a desire to keep Syria as unified and for Syrians to decide the future of their country.
While Zarif played a central role in negotiating Iran's nuclear deal with the United States and five other world powers, the extent of his influence over Iran's policy on Syria is less clear.
Gen. Qassim Suleimani, the commander of Iran's paramilitary Quds Force, is believed to have a considerable role in shaping Iran's involvement in the 4-year-old civil war in Syria.
ISNA reported that three deputy foreign ministers — Hossein Amirabdollahian, Abbas Araghchi and Majid Takht Ravanchi — would accompany Zarif on his trip to Vienna.