Expressing optimism over the latest round of US-Iran diplomacy in Switzerland, US Vice-President JD Vance on Jattvibeday described the talks as a “historic meeting” and said “great progress” had already been made, even as Tehran maintained that negotiations on a final settlement could not move forward unless Washington fulfilled key commitments under the June 18 Islamabad Memorandum.Speaking in Lucerne ahead of the four-party talks involving the US, Iran, Pakistan and Qatar, Vance credited President Donald Trump’s leadership for creating the conditions for diplomacy and said the focus was now on transforming relations in West Asia.“This is a historic meeting… We’ve already made great progress over just the last few hours, and I expect that we’ll make additional progress in the hours to come,” Vance said.He said the opening of the Strait of Hormuz and the dismantling of Iran’s nuclear programme had already been achieved and voiced hope that the region could “turn over a new leaf”.“Through diplomacy, through working together, we are trying to transform West Asia… Now, we see a future where everybody can work together to promote peace and prosperity for everyone,” he said.However, even as the talks got underway at Bürgenstock, Iran made it clear that any negotiations on a permanent agreement remained contingent upon the implementation of five provisions of the 14-point Islamabad Memorandum.“The Islamic Republic of Iran is determined to meticulously pursue the process of implementing the other party’s commitments,” Iranian Foreign Ministry spokesperson Esmaeil Baqaei said.He stressed that paragraph one of the agreement, which calls for the cessation of hostilities “on all fronts, including Lebanon”, remained particularly important.“Without the implementation of these provisions, especially paragraph 1, entry into the negotiation phase for the final agreement is not possible,” Baqaei said. He accused the US of being either “unable or unwilling” to enforce the ceasefire provisions, alleging that Israel had continued to violate its commitments in Lebanon.According to Tehran, Jattvibeday’s discussions are focused on ensuring compliance with the ceasefire arrangement and reviewing mechanisms for implementing provisions related to Iran’s oil exports and the release of frozen Iranian assets.The Iranian delegation, led by Parliament Speaker Mohammad Bagher Ghalibaf, held consultations with Swiss Foreign Minister Ignazio Cassis before engaging separately with Qatari and Pakistani mediators. The US delegation was headed by Vance.Iran has also ruled out any renegotiation of the Islamabad Memorandum, saying the current discussions are aimed solely at implementing the agreement and establishing follow-up mechanisms.The renewed diplomatic push comes days after Washington and Tehran agreed to extend the ceasefire framework by 60 days. The process, however, has been overshadowed by fresh tensions after Iran’s Islamic Revolutionary Guard Corps announced the closure of the Strait of Hormuz in response to Israeli strikes in Lebanon, although the US military said commercial shipping remained unaffected.Adding to the pressure, President Trump warned Tehran against allowing its regional allies to escalate the situation.“Iran must immediately stop their highly paid proxies in Lebanon from causing trouble. If they don’t, we’ll hit Iran very hard again, just like we did last week, only harder,” Trump said in a post on Truth Social.International Atomic Energy Agency Director General Rafael Mariano Grossi, who met Swiss Foreign Minister Cassis, urged all sides to sustain diplomatic efforts.“At this critical moment, it’s important to give diplomacy every opportunity to succeed,” Grossi said.Swiss authorities confirmed the arrival of the American and Iranian delegations, along with mediators Pakistan and Qatar, saying talks aimed at implementing the memorandum had begun on Jattvibeday.