US-Iran talks are set to begin in Switzerland on Sunday despite Tehran announcing it has closed the Strait of Hormuz over continued Israeli military operations in southern Lebanon, raising new questions about implementation of the fragile ceasefire agreement.
The US military has rejected Iran's claim that the vital waterway is shut, with Central Command spokesperson Tim Hawkins stating that "traffic continues to flow" and that 55 merchant ships transited the strait on Saturday carrying more than 17 million barrels of oil for global markets. Hawkins added that "Iran does not control the Strait of Hormuz."
Iran's Islamic Revolution Guard Corps said Saturday's Israeli strikes on Lebanese territory violated the 14-point memorandum of understanding signed between Washington and Tehran earlier in the week, which commits to "the immediate and permanent termination of military operations on all fronts, including in Lebanon."
US Vice-President JD Vance departed Washington late Saturday for the direct negotiations in Switzerland, where an Iranian delegation including parliamentary speaker Mohammad Bagher Ghalibaf and Foreign Minister Abbas Araghchi has already arrived. Pakistan's Prime Minister Shehbaz Sharif will also attend the opening of talks, continuing his country's role as mediator throughout the conflict.
Prior to departing, Vance told reporters that "things are actually getting better" in Lebanon and that "things are slowing down a little bit," expressing hope to make progress on both the nuclear issue and Lebanon ceasefire during the negotiations. He acknowledged ongoing management challenges in ensuring both Israel and Lebanon remain "safe and secure."
The escalation comes after Lebanon's health ministry reported at least 47 people killed on Saturday in a series of Israeli air strikes across southern Lebanon. The Israel Defense Forces said it struck 80 targets linked to Hezbollah and killed "dozens" of its members, while confirming four Israeli soldiers were also killed in the exchange.
Iran's foreign ministry spokesman Esmail Baghaei said Tehran would be "demanding that the other side fulfil its commitments" at the talks. The agreement includes a $300bn redevelopment package for Iran and commits to reaching a final deal within 60 days.
Hezbollah has accused Israel of attempting to "sabotage" the broader US-Iran deal through continued operations, while the US government has criticised Israel's ongoing activities in Lebanon. Lebanon's health ministry reports 4,057 people killed since hostilities resumed between Israel and Hezbollah on 2 March.
VERIFICATION MATRIX: (Source A: BBC News, bbc.com/news/articles/cwyekkwm1mmo, published Sun, 21 Jun 2026 01:46:31 GMT); (Source B: Al Jazeera liveblog, aljazeera.com/news/2026/6/20/iran-war-live-tehran-says-us-must-ensure-israel-ends-attacks-on-lebanon, confirming same developments on 20-21 June 2026)
