US and Iran launch Switzerland talks as Hormuz closure adds tension and Lebanon ceasefire frays

Diplomatic push in Switzerland

US Vice President JD Vance landed at Emmen Air Base outside Lucerne early Sunday to formally open talks with Iran aimed at curbing Tehran's nuclear programme and cementing the interim ceasefire signed last week. The Iranian delegation, led by parliament Speaker Mohammad Bagher Qalibaf and Foreign Minister Abbas Araghchi, had already reached Zurich, state media reported. Negotiations take place at the Burgenstock luxury hotel complex, with Pakistani Prime Minister Shehbaz Sharif, army chief Field Marshal Asim Munir, and Qatari Prime Minister Sheikh Mohammed bin Abdulrahman bin Jassim Al Thani joining as mediators. US special envoy Steve Witkoff and Jared Kushner, the president's son-in-law, were already on the ground ahead of Vance, whose departure from Washington was delayed by the escalation in Lebanon.

I hope to make progress on the nuclear issue and on the Lebanon ceasefire issue.

Strait of Hormuz closure and the American denial

On Saturday, Iran's Islamic Revolutionary Guard Corps announced it would close the Strait of Hormuz to maritime traffic, calling the move a first measure in response to violations of the ceasefire by the enemy. The waterway handles roughly a fifth of the world's traded oil and natural gas. US Central Command immediately disputed the claim, stating that 55 merchant ships had transited the strait safely on Saturday carrying more than 17 million barrels of oil and that American forces would continue to monitor the situation to ensure traffic flows. President Donald Trump wrote on social media that no toll would be charged for passage during the 60-day ceasefire, but he left open the possibility of a US-imposed toll for services rendered as the Guardian Angel to the Middle East if the peace deal fails.

Lebanon clashes threaten the truce

The closure announcement came after heavy fighting between Israel and the Iran-backed Hezbollah. The Israeli military said more than 50 projectiles were fired at its troops overnight Friday, while Lebanese authorities reported at least 24 dead on Saturday and 83 on Friday; other sources put Saturday's toll at 83. Since the war began on 2 March, 4,057 people have been killed in Lebanon, according to the Lebanese health ministry. Both sides accuse each other of sabotaging the truce. Israeli foreign ministry spokesperson Oren Marmorstein wrote on X that Hezbollah continues to constantly violate the ceasefire, while the group said Israel was totally responsible for the breaches.

Hezbollah continues to constantly violate the ceasefire.

The fragile interim deal

The memorandum of understanding, signed electronically by Trump and Iranian President Masoud Pezeshkian on Wednesday, contains a 14-point plan, with Clause 1 calling for an end to hostilities on all fronts, including Lebanon. Adviser to Supreme Leader Ayatollah Mojtaba Khamenei, Mohammad Mokhber, accused the US of failing to implement the clause and warned that as long as the agreement remained only on paper, the flow of Middle East energy would stay halted. Iran's foreign ministry spokesperson Esmaeil Baghaei said the delegation would press for implementation and seek clarity on how the other side intended to carry out its commitments.

Clause number 1 of the memorandum of agreement is the most important part of the mutual commitments of both parties, namely ending the war on all fronts, including in Lebanon.

As long as the agreement is only on paper, the flow of Middle East energy will remain halted.

Timeline of the crisis

The sequence of events underscores the fragility of the peace process. The Israel-Hezbollah war, part of the broader four-month US-Israel conflict with Iran, has pushed oil prices above $100 a barrel. Egypt is hosting a four-way meeting of the foreign ministers of Saudi Arabia, Turkey, and Pakistan alongside the Swiss talks, reflecting the regional stakes.