US President Barack Obama warned Iran on Tuesday not to walk away from agreements reached in principle in Lausanne, Switzerland, back in April, as diplomats tried to reach a common text for a final nuclear deal.In Lausanne on April 2, world powers and Iran announced a series of political commitments they said would ultimately frame a comprehensive nuclear accord. Negotiators from the US, Britain, France, Russia, China, Germany and Iran are now in Vienna to hammer out that final agreement.But Obama, speaking from the East Room of the White House on Tuesday, said that “a lot of talk on the other side from the Iranian negotiators” in recent days suggested they were straying from the framework.“The framework agreement that was established at Lausanne was one that, if implemented, would in fact achieve my goal,” he said.Obama’s stated goal is to prevent Iran from acquiring a nuclear weapon. But if Iran cannot abide by the Lausanne framework, “that’s going to be a problem,” the president said.“I will walk away from the negotiations if, in fact, it’s a bad deal,” he said. “If the verification regime is inadequate, then we’re not going to get a deal.”The president’s warning came on June 30, the day negotiators had set as a deadline for them to reach a final nuclear accord. But diplomats from all sides agreed to extend the interim agreement – known as the Joint Plan of Action, clinched two years ago to freeze the crisis in place and to allow for comprehensive negotiations – by one week. Speaking to a small group of reporters in the Austrian capital on Monday, one senior administration official said – in English, and in Farsi, through an aide – that the Lausanne framework could not be edited as negotiations entered their final act.“There wasn’t paper out of Lausanne. You didn’t have a text. You had parameters,” the official said on the condition of anonymity due to the sensitivity of the talks.“You are going to have a text,” the official added, noting the “staggeringly consequential” nature of the agreement they are trying to broker.Obama made the remarks in a joint press conference in Washington with President Dilma Rousseff of Brazil.“Ultimately, this is going to be up to the Iranians,” Obama said.At the time of the framework negotiations in Switzerland, Iran’s supreme leader, Ayatollah Ali Khamenei, publicly opposed any two-step process that began with a framework of principles. He sought a single agreement, announced in a single phase. But the US insisted on an agreement that settled most, if not all, questions of political will.The result was a press conference that included statements from the European Union’s high representative on foreign affairs, Iran’s foreign minister and the US secretary of state. Their statements were made alongside written parameters released separately by the White House and the Iranian government.But the parameters out of Washington and Tehran had differences. World powers are negotiating with Iran in an effort to cap, restrict, monitor and partially roll back its nuclear program for a finite period in exchange for sanctions relief. In Iran, President Hassan Rouhani issued a warning of his own shortly after Obama’s comments.“We will return to our previous path more forceful than what they may imagine” if a deal is broken, he said, according to state-run Iranian media.Iran’s full delegation arrived in Vienna on Tuesday, expressing optimism upon its arrival at the Palais Coburg, a small luxury hotel hosting the talks.While US negotiators have agreed to work through the week, they say they will not leave Vienna without concluding the diplomatic effort, and have ruled out a long-term extension.Iranian Foreign Minister Mohammad Javad Zarif was accompanied by Ali Akbar Salehi, the country’s chief technical expert at the talks, as well as President Hassan Rouhani’s brother and several of their aides.Zarif told Iranian press that he had been in Tehran for consultations on Monday. But he denied that he had traveled back to Iran for 24 hours to receive a mandate to close the deal from Khamenei.“I didn’t go to get a mandate,” he said. “I already had a mandate to negotiate. And I’m here to get a final deal, and I think we can.”During Zarif’s bilateral meeting with US Secretary of State John Kerry, which lasted an hour, Khamenei sent out a message on Twitter blessing his negotiating team.“I recognize our negotiators as trustworthy, committed, brave and faithful,” he said, along with a photo of the team in white lab coats and the hashtag #IranTalks.On Monday, one senior administration official said that their team expected a “roller coaster” final round.A rally was held on Tuesday in Tehran, attended by supports of the supreme leader’s strict conditions for a nuclear deal. Those include a rejection of access to military sites sought by international inspectors, and immediate sanctions relief upon the signing of an agreement.US negotiators say there will be no “signing,” however. Instead, a deal will involve an adoption phase, an implementation phase and then a phase when all provisions of the agreement take effect.Russia’s Foreign Minister Sergei Lavrov and Germany’s Foreign Minister Frank-Walter Steinmeier both arrived in Vienna on Tuesday. They met with Kerry and Zarif separately. American diplomats negotiating with Iran over its nuclear program in Austria have been in constant communication with their Israeli counterparts, The Jerusalem Post has learned.A senior US official told the Post on Tuesday that Under Secretary of State for Political Affairs Wendy Sherman, President Barack Obama’s chief negotiator with Iran, “spoke in a secure call with [Israeli National Security Adviser] Yossi Cohen last week.”“And experts have remained in continuous communication,” the official continued.Prime Minister Benjamin Netanyahu and Defense Minister Moshe Ya’alon have criticized the emerging deal with Iran in recent days.They warn it will legitimize Tehran’s nuclear program in the short term, endorse its expansion in the long term and ensure the Islamic regime stays in power for good.The Obama administration says it will only agree to a deal that guarantees Iran cannot obtain a nuclear weapon. And the US team says their talks strictly concern the nuclear file.