Saudi Arabia and the United Arab Emirates pressed Iran on Tuesday to accept a sharply expanded inspections regime at its remaining nuclear facilities, joining a new round of post-ceasefire diplomacy in Vienna that Western officials described as the most consequential since fighting halted two weeks ago.

The talks, convened under Austrian auspices and chaired by senior diplomats from Pakistan and Egypt, opened at the Palais Coburg with delegations from Iran, the United States, the United Kingdom, France, Germany, China and Russia, along with observers from the European Union and the Arab League. They are the first formal multilateral session since the April 12 Islamabad framework that ended six weeks of war between Iran and Israel.

“The region cannot return to the conditions that produced this war,” Saudi Deputy Foreign Minister Waleed al-Khuraiji told reporters outside the hotel. “What we are asking for is not punitive. It is the verification that allows everyone, including Iran, to rebuild with confidence.”

The Saudi-Emirati intervention, jointly coordinated with Cairo, marks a significant shift in Gulf diplomacy. For years, Riyadh and Abu Dhabi largely deferred to the United States and the E3 European powers on Iran’s nuclear file. Diplomats from three delegations said the Gulf states are now seeking a formal seat at any successor agreement to the lapsed 2015 nuclear deal, citing the cost they bore during the war, including dozens of Houthi and Iranian missile and drone launches intercepted over their territory.

Iranian Foreign Minister Abbas Araghchi, arriving Monday night, struck a measured tone. He told Iranian state television that Tehran was prepared to discuss “reasonable transparency measures” but rejected what he called “any framework that treats Iran as a defeated power.” Iran has consistently described the ceasefire as a mutual stand-down rather than a capitulation, a position the United States has not publicly contested.

A senior State Department official, speaking on condition of anonymity to describe private discussions, said the U.S. delegation, led by Deputy Secretary of State Christopher Landau, had presented Tehran with a written set of “minimum verification expectations” that included continuous monitoring at the Natanz and Fordow sites, snap inspections at four additional facilities, and a cap on uranium enrichment at 3.67 percent for an initial five-year period. In exchange, the official said, Washington would support a phased lifting of secondary sanctions and clear the way for World Bank and Asian Infrastructure Investment Bank participation in Iranian reconstruction.

“There is a deal to be had here,” the official said. “It will not look like the JCPOA. It will be narrower in scope but harder to walk away from.”

The Vienna meeting follows a flurry of regional travel. Egyptian Foreign Minister Badr Abdelatty visited Tehran on Sunday, and Pakistani Prime Minister Shehbaz Sharif hosted a working dinner in Islamabad on Saturday with Saudi Crown Prince Mohammed bin Salman and Qatari Emir Tamim bin Hamad Al Thani. The communique from that meeting endorsed “a verifiable and durable settlement” and pledged a combined $14 billion in initial Gulf contributions to a multilateral reconstruction fund covering Iran, Iraq and Yemen.

Israel is not participating in the Vienna track but has been briefed daily by U.S. officials. Israeli Foreign Minister Gideon Sa’ar said in Jerusalem that Israel would judge any agreement “by its enforcement, not its language,” and reiterated that Israel reserves the right to act unilaterally against what it deems imminent threats. The statement drew a sharp response from the Iranian delegation, with a senior Iranian official telling reporters that “ceasefires are not made stronger by threats.”

European diplomats said the most difficult issue at the table is not enrichment but Iran’s ballistic missile program, which was not addressed in the Islamabad framework. Germany and France have circulated a draft annex that would commit Iran to refrain from testing missiles with a range exceeding 2,000 kilometers and to allow declarations of its stockpile. Russia, which has aligned with Iran on several procedural points, has signaled it would prefer that missile constraints be handled in a separate forum.

“The Europeans want a comprehensive package; the Russians want a narrow one; the Iranians want the narrowest possible,” said Layla Hassan, a Beirut-based regional analyst with the Mediterranean Council. “The question is whether the Gulf states can broker a middle position. They have leverage they did not have a year ago.”

Energy markets reacted modestly to the opening of the talks. Brent crude, which closed at $96.40 a barrel Monday, fell another 70 cents in London trading as traders priced in a slightly higher probability of a durable settlement. John Reilly, an analyst at Citi, said in a client note that a successful Vienna round could push Brent toward the high $80s by mid-summer, though he cautioned that “the path from a ceasefire to a verified agreement is rarely linear.”

Inside Iran, the talks have become a political flashpoint. Conservative outlets in Tehran on Tuesday published commentary accusing the government of trading sovereignty for reconstruction loans, while reformist newspapers welcomed the negotiations as overdue. President Masoud Pezeshkian, who has staked considerable political capital on a settlement, is scheduled to address parliament on Wednesday.

Diplomats said the Vienna round is expected to run at least through Friday, with technical working groups continuing into next week. A second ministerial session, tentatively planned for Doha in mid-May, would attempt to finalize a framework text. Officials cautioned that several core issues, including the fate of advanced centrifuges removed during the war and the status of Iranian-backed militias in Iraq and Yemen, remain unresolved.

Austrian Foreign Minister Alexander Schallenberg, opening the session, urged the delegations to “treat this not as the end of a war but as the beginning of a peace that must be built.” Officials said additional briefings would be held later in the week as drafting work advanced.