A fresh wave of Israeli military bombardment across southern Lebanon has thrown a critical new set of Iran-US peace negotiations into disarray, forcing both delegations to delay their planned departure for opening talks in Switzerland. The violence, which left at least 18 Lebanese civilians dead, comes just weeks after the Trump administration and Iranian leadership signed a preliminary memorandum of understanding (MOU) to outline a path toward ending the ongoing Iran war, which began when the U.S. and Israel launched joint military operations in late February.
The incident also sparked open friction between senior U.S. officials and Israeli leadership. U.S. Vice President JD Vance, who was originally set to join the American delegation to Switzerland, publicly criticized Israeli leaders for a pattern of launching large-scale bombing attacks during key moments of diplomatic progress. Vance’s remarks echoed a similar disruption that unfolded just last weekend: shortly after U.S. President Donald Trump announced plans to sign the MOU, Israeli forces carried out a deadly strike on central Beirut.
“We seem to be right on the cusp of a major breakthrough in the agreement, and then all of a sudden, there’s a major explosion that goes off in a civilian population center in Beirut, and a lot of people who have nothing to do with Hezbollah lose their lives,” Vance told reporters on Thursday. “That’s not acceptable.”
Friday’s bombardment targeted heavily populated residential areas across southern Lebanon’s Nabatieh district, according to on-the-ground reporting from Roqayah Chamseddine, a writer based in the region. Chamseddine documented mass civilian casualties in the towns of Dweir Harouf, Al-Sharqiya, and Kfar Sir, with additional strikes hitting Kfar Roumman, Haboush, Jebchit, Toul, and Deir al-Zahrani. Many of the residents in these areas had only just begun returning to their homes after previous ceasefire efforts, before the new offensive expanded into the Western Bekaa Valley, with warplanes targeting Abu Rashed Heights and launching strikes along the Litani River valley near Zalaya.
Hours after the initial Israeli strikes, Hezbollah carried out an anti-tank attack that killed four Israeli soldiers in southern Lebanon, according to official statements from the Israel Defense Forces. The attack triggered harsh rhetoric from Israel’s far-right National Security Minister Itamar Ben-Gvir, who called for widespread retaliation. “All of Lebanon must burn,” Ben-Gvir declared, adding, “With all due respect to the Americans, Israel must make it clear to the entire world that the blood of our sons and the security of our citizens are not forfeited.”
Officially, the Trump White House only cited unspecified logistical challenges to explain the delay of the U.S. delegation’s departure, making no public mention of the Lebanese bombardment. But Lebanese outlet Al Mayadeen, citing an anonymous Iranian government source, confirmed that the latest Israeli assault was the direct cause of Tehran’s decision to postpone its delegation’s trip.
The 60-day opening round of technical talks was meant to work out detailed implementation of the MOU, which calls for “the immediate and permanent termination of military operations on all fronts, including in Lebanon.” Iranian leadership has repeatedly made clear that a full end to Israeli attacks on Lebanese territory is a non-negotiable precondition for advancing a final peace deal. Mediators have now shifted focus to rescheduling the talks, as escalating violence in Lebanon threatens to erase what little diplomatic momentum had been built to end the months-long conflict.