Barack Obama holds historic phone conversation with Iran leader Hassan Rouhani An indication of the tone of the conversation was revealed on official Twitter account of Mr Rouhani. In one tweet, though since deleted, Mr Rouhani revealed that Mr Obama had ended the conversation with the Persian sign-off "Khodahafez" - or "May God look over you." Mr Rouhani, for his part, had signed off in true American style, with the words: "Have a nice day!." The conversation came a day after Iran's foreign minister Mohammad Javad Zarif held what all sides described as a "positive" meeting with the foreign ministers from Britain, China, France, Germany, Russia and the United States - the so-called P5+1 grouping. Following the meeting at which Mr Zarif sketched out a plan to break the deadlock over Iran's nuclear enrichment, a fresh round of talks has been announced in Geneva next month on October 15 and 16. The remarkable warming of relations between Washington and Tehran has followed a softening of rhetorical tone following Mr Rouhani's election last June on the back of rising middle class discontent in the face of crippling international economic sanctions. Before his conversation with Mr Obama, the Iranian president used a press conference on the fringes of the UN to reiterate what he said was Iran's commitment to cutting a deal in Geneva in the next few months. "We will never deviate from our commitments," he added. Mr Obama said there was a real prospect of a deal that would not only reset US-Iranian relations but work as a catalyst for "greater peace and stability" across the wider Middle East. "I do believe that there is a basis for resolution," Mr Obama added, "Iran's supreme leader has issued a fatwa against the development of nuclear weapons. President Rouhani has indicated that Iran will never develop nuclear weapons. I've made clear that we respect the right of the Iranian people to access peaceful nuclear energy in the context of Iran meeting its obligations. However the president noted that "important obstacles" would have to be overcome if the promise of the last few weeks was to be fulfilled, but dangled the possibility of sanctions relief if Iran genuinely complied with its international obligations. The test will be meaningful, transparent and verifiable actions, which can also bring relief from the comprehensive international sanctions that are currently in place. Before the two presidents spoke, Iran also had held a "very constructive" round of talks with the International Atomic Energy Authority (IAEA) in Vienna as part of the ongoing negotiations with Iran, according to Herman Nackaerts, the IAEA deputy director general. The IAEA has a list of outstanding questions for Tehran about its nuclear enrichment programs and called for Iran to do more to share information with the agency, according to their last quarterly report released in August. The P5+1 powers are expected to ask Iran to resolve these outstanding questions as the first step towards confidence-building measures, and, after weeks of diplomatic choreography, the first major test of Iranian sincerity in reaching a deal over its nuclear programme.