Talks between the U.S. and Iran that were set to be held Friday in Switzerland were called off amid the escalation, threatening to derail progress after an agreement was reached earlier in the week to reopen the Strait of Hormuz. The White House said Vice President Vance, who is leading the U.S. negotiating team, would not be traveling to Switzerland to meet Iranian counterparts as planned. The Swiss foreign ministry confirmed the talks were postponed and said it stood ready to facilitate should they resume.

Fighting between Israel and the Iran-backed militant group Hezbollah has become a major sticking point in negotiations and driven a wedge between Netanyahu and Trump. Their interests have diverged as Netanyahu seeks to keep up pressure on Iran and Hezbollah, while Trump looks for a way out of the war. Tehran insists that any peace deal with Washington must include Lebanon, while Israel says it will keep up the fight there.

“This was a train wreck waiting to happen,” said Danny Citrinowicz, a former Israeli military-intelligence official and a senior researcher at the Institute for National Security Studies, a think tank in Tel Aviv. “If the U.S. wants an agreement, it will have to force Israel to completely stop and withdraw, and Netanyahu is not interested in that.”

The waves of strikes overnight marked one of the most serious escalations in Lebanon since a ceasefire in April. Israel’s military said four of its soldiers were killed in a Hezbollah drone strike, and that it had killed dozens of Hezbollah militants and struck more than 80 targets in response to what it said were repeated violations of the pact.

“My directive is clear: Israel will not tolerate attacks on our soldiers or our territory, and it will exact a very heavy price from Hezbollah for these assaults,” Netanyahu said on Friday.

The Israeli strikes targeted two command centers in the Bekaa Valley, in eastern Lebanon, as well as scores of other sites in the country’s south, the Israeli military said. Hezbollah said on Thursday that it was fighting Israeli troops as they tried to advance farther inside Lebanese territory.

Lebanon’s health ministry said at least 18 people were killed and dozens injured in strikes on at least 11 locations across the country’s south, where Israeli troops have occupied what they call a security zone several miles wide along the border. The ministry did not say how many of those killed were combatants.

The fighting in Lebanon has deepened a standoff between Trump and Netanyahu, as pressure mounts in Washington to end the war and ease its economic fallout. Conversations between the two leaders have become increasingly hostile, with Trump pressing Netanyahu to “stop blowing up buildings.”

The memorandum of understanding reached between the U.S. and Iran this week is meant to usher in a 60-day period in which the Strait of Hormuz will reopen in exchange for allowing Iranian oil sales, providing Tehran with much-needed economic relief. The agreement also stipulates an end to fighting in Lebanon and that its “territorial integrity and sovereignty” must be ensured, language that drew criticism from Israel’s security establishment. Netanyahu himself has not publicly criticized the deal, but ministers in his government have pushed to keep up fighting against Hezbollah.

“For every tear of an Israeli mother, a thousand Lebanese mothers must weep. All of Lebanon must burn!” Itamar Ben-Gvir, Israel’s far-right minister of national security, said in a post on social media Friday. “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.”

Vance lashed out at Israeli critics on Thursday, pointing out that the country relies on American weapons to defend itself. “Donald J. Trump is the only head of state in the entire world who’s sympathetic to the nation of Israel at this moment in time,” Vance said. “If I was in the cabinet of the Israeli government, I might not be attacking the only powerful ally that I have anywhere left in the entire world.”