The Swiss foreign ministry announced on Friday that the planned technical negotiations between the United States and Iran at the Bürgenstock resort would not take place, confirming the postponement of a meeting intended to begin implementing the 14-point memorandum signed two days earlier. The US vice-president, JD Vance, cancelled his travel, and Iran did not dispatch its delegation. According to three diplomatic sources cited by the Financial Times, Tehran suspended its participation in response to a wave of Israeli air strikes on southern Lebanon, which Iranian officials regard as a direct violation of the accord’s first clause requiring an immediate and permanent cessation of military operations on all fronts, including Lebanon.

Viewed from Tehran, the Lebanon dossier is non-negotiable. Iranian officials conveyed to mediators that there would be “no Lebanon, no deal” and that the Islamic Republic expects Washington to restrain Israel before technical talks can proceed. Supreme Leader Ayatollah Mojtaba Khamenei described the agreement as a sign of American desperation and warned that Iran would not accept excessive demands in future nuclear negotiations. From Washington, the White House attributed the delay to unresolved logistical arrangements, though President Donald Trump later stated that the meeting had failed because of Iran. US officials maintain that a delegation remains ready to travel. In Israel, which is not a party to the memorandum, Prime Minister Benjamin Netanyahu declared that troops would stay in a southern Lebanon security zone for as long as necessary, and far-right ministers insisted that security requirements override diplomatic pressure. The Israeli military reported striking more than 80 Hezbollah targets overnight, while Hezbollah claimed attacks on Israeli armour that killed four soldiers, including a battalion commander.

The postponement clouds the 60-day negotiation window established by the memorandum, which was to address Iran’s nuclear programme, sanctions relief, and a permanent settlement. The deal’s ceasefire provision is being tested immediately: Lebanese health authorities reported at least 18 fatalities from the Israeli strikes, and Hezbollah described intense clashes along the border. The divergence between Washington and its ally Israel is widening; US officials have privately expressed irritation that Israeli operations nearly derailed the agreement. Meanwhile, the reopening of the Strait of Hormuz has allowed some tanker traffic to resume, contributing to a decline in oil prices, but maritime insurers and shipowners are demanding urgent clarity on mine clearance and safe passage, as full security depends on Iran fulfilling its commitment to remove explosive devices from the waterway.

Broader context underscores the fragility of the process. The war began on 28 February with US and Israeli air strikes on Iran, and the memorandum—signed remotely by Presidents Trump and Masoud Pezeshkian—offers Iran substantial sanctions relief, the unfreezing of assets, and a $300 billion reconstruction fund in exchange for reaffirming it will not seek nuclear weapons and accepting on-site down-blending of enriched uranium under IAEA supervision. In Washington, Republican lawmakers have questioned whether the president conceded too much after previously demanding unconditional surrender, while Tehran frames the deal as leverage gained by surviving a direct military campaign. Switzerland has stated it remains ready to facilitate talks and that preparatory work at Bürgenstock continues. Mediators from Qatar and Pakistan are working to resolve the impasse over Lebanon, but no new date has been set. The resumption of dialogue now depends on whether a durable halt to hostilities in Lebanon can be secured, placing the diplomatic track at the intersection of US-Iran engagement and an Israeli security agenda that operates independently of the memorandum.