Lebanon Crisis Threatens Fragile US-Iran Ceasefire Agreement]
The preliminary agreement between Iran and the United States nearly collapsed shortly after coming into effect on Friday, with Lebanon emerging as the critical obstacle threatening to derail the diplomatic breakthrough. For the second time in recent weeks, the ongoing conflict in Lebanon has disrupted high-stakes negotiations between Tehran and Washington.
Fighting between Iran-backed Hezbollah and Israel intensified on Friday, leading to the postponement of new talks in Switzerland between the United States and Iran. While neither side publicly cited a reason, three diplomats indicated that Iran withdrew from the negotiations following Israeli airstrikes in Lebanon.
“Iran’s new leadership views Lebanon as integral to its national security,” explained Mohanad Hage Ali, a senior fellow at the Carnegie Middle East Center in Beirut. “Previous Israeli advances against Hezbollah in 2024 paved the way for direct conflict with Iran. The end goal for Iran is an Israeli withdrawal from Lebanon.”
This latest disruption marks the second occurrence in recent weeks where Lebanon has undermined Us-Iran talks. Earlier this month, Israeli strikes near Beirut prompted Iran to launch missile attacks on Israel, triggering reciprocal strikes across Iran itself.
The diplomatic breakdown occurred days after the United States and Iran signed a preliminary agreement calling for “immediate and permanent termination of military operations” in Lebanon while pledging to protect the country’s territorial integrity and sovereignty. The inclusion of Lebanon represented a diplomatic victory for Iran, which insisted the deal cover the country where Hezbollah—its allied militant group—launched attacks on Israel in March in solidarity with Tehran.
Prime Minister Benjamin Netanyahu of Israel, who was not party to the negotiations, strongly opposed these terms and vowed to continue operations against Hezbollah. On Friday, Israeli Ambassador to the United States Yechiel Leiter announced a cease-fire and halt to offensive operations, attempting to preserve the fragile Us-Iran deal. However, he confirmed Israeli forces remain in southern Lebanon “to dismantle Hezbollah’s terror infrastructure,” stating, “We will remain there until that mission is accomplished.”
Hezbollah did not immediately respond. The agreement’s terms have raised significant questions about implementation. Neither Israel nor Hezbollah signed the memorandum, and the deal does not specify compliance mechanisms. It also fails to resolve fundamental issues: whether Israel will withdraw from southern Lebanon and whether Hezbollah will surrender its weapons.
Washington and Israel sought to separate the two conflicts, while Tehran used Israel’s Lebanon campaign as leverage in negotiations with Washington. This approach increased President Trump’s frustration with Prime Minister Netanyahu, prompting concerns that Israeli actions could jeopardize the agreement.
Since the agreement’s announcement, Israel has ceased daily evacuation warnings for towns across southern Lebanon, though airstrikes and reduced-scale operations have continued. Hezbollah reported ambushing Israeli troops in Nabatieh, killing four soldiers, prompting over 150 Israeli strikes that killed at least 47 people, according to Lebanon’s health ministry.
The U.S.-Iran deal’s uncertainty remains. Retired Israeli Brig. Gen. Assaf Orion noted that while Iran successfully linked the theaters and constrained Israel, it’s “too early to judge” whether restraint will persist and for how long.
A previous cease-fire between Lebanon and Israel, brokered by the Trump administration in April, offers a cautionary example. Despite provisions barring offensive operations while preserving self-defense rights, Israel invoked broad exceptions to continue strikes and expand its ground invasion.
Next week, Israeli-Lebanese talks on a stable Lebanon solution will occur in Washington following Secretary of State Marco Rubio’s talks with Lebanese President Joseph Aoun. Analysts note Tehran’s increased influence over Hezbollah since the group’s former leader Hassan Nasrallah was killed in Israeli airstrikes in 2024.
After Hezbollah and Israel agreed to a previous cease-fire, Hezbollah maintained restraint despite daily Israeli airstrikes until the U.S.-Israeli conflict with Iran began in late February.
“It’s unlikely the Lebanon conflict will be resolved soon,” observed Lina Khatib, associate fellow at Chatham House. “The U.S.-Iran deal may create de-escalation conditions but doesn’t address core issues like Israeli withdrawal or Hezbollah’s weapons.” Israeli forces occupy southern Lebanon—the largest deployment in over two decades. Border towns have been devastated, displacing over a million people.
Israel shows no intention of withdrawing, challenging the agreement’s commitment to Lebanese sovereignty. Hezbollah maintains its arsenal is necessary given the occupation, while Lebanon’s government pledges weapons control but lacks capacity to enforce it.
