Ongoing fighting between Israeli forces and Hezbollah in southern Lebanon is threatening a tentative agreement between the United States and Iran to end the war.
The memorandum between the two countries includes a ceasefire in Lebanon that protects Hezbollah, Iran’s longtime ally, from Israeli attacks as long as it does not fire on Israel.
The fighting has already led to the postponement of U.S.-Iranian talks that would begin the difficult process of resolving long-standing issues such as Iran’s nuclear program and sanctions.
As fighting continues in southern Lebanon and the status of negotiations remains uncertain, here’s how we got here.
Hezbollah, an Iranian-backed Shiite Islamic movement, is one of the most powerful militias in the Middle East and has been in conflict with Israel for decades since establishing itself as a force in Lebanon in the 1980s.
It has long been focused on destroying Israel, building a powerful arsenal of rockets, missiles and drones with Iranian support.
Israel has launched frequent operations against Hezbollah, most notably in 2006, when Hezbollah’s cross-border raids and capture of two Israeli soldiers triggered a large-scale Israeli air and ground operation that lasted more than a month.
An independent Israeli investigation called the operation “a grave missed opportunity. Israel began a long war that ended without a clear military victory.”
Hezbollah survived and began cross-border rocket fire in October 2023, after Israel began shelling Gaza in response to Hamas’ attacks on southern Israel. A year of fighting ensued, during which Israel killed Hezbollah’s longtime leader Hassan Nasrallah.
In November 2024, Israel approved a ceasefire agreement that obliges it to withdraw from southern Lebanon. But the Israeli military maintained that Hezbollah was in violation of the agreement and continued to hold the position past the deadline, conducting almost daily airstrikes.
A new cycle of violence began after Israel and the United States killed Iranian Supreme Leader Ayatollah Khamenei in an airstrike at the end of February.
In early March, Hezbollah began shelling northern Israel in response to attacks on Iran.
The Israeli military retaliated by launching heavy airstrikes on purported Hezbollah positions and sending troops deep into Lebanese territory in an effort to establish a buffer zone. Since then, much of southern Lebanon has been cleared of its population and thousands of homes in southern Lebanon’s villages have been demolished.
More than 3,900 people have been killed in Lebanon since the military escalation began, according to the Health Ministry.
The first paragraph of the 14-point memorandum indicates that ending hostilities in Lebanon is the most important aspect of the agreement.
The agreement states that the United States, Iran, and their allies “declare an immediate and permanent cessation of military operations on all fronts, including in Lebanon, and commit to refraining from future wars or military operations against each other, refraining from the threat or use of force against each other, and ensuring the territorial integrity and sovereignty of Lebanon.”
US President Donald Trump also said on social media Thursday that he “expects a complete ceasefire on all fronts, including Lebanon, Hezbollah and Israel” as part of the deal.
For Tehran, halting Israeli attacks on its most important ally in the region has always been a central demand in tough negotiations to end the three-month conflict.
On Friday, a diplomat familiar with the matter told CNN that Iran had sought assurances that hostilities in Lebanon would end before resuming talks with the United States.
For the Israeli government, the lack of freedom to act to further disparage Hezbollah is abhorrent and a serious test of its close alliance with the United States.
Israel’s far-right National Security Minister Itamar Ben Gvir said on Friday: “With all due respect to the American people, Israel must make clear to the whole world that it does not have to sacrifice the blood of its sons and the security of its people.”
Israeli Prime Minister Benjamin Netanyahu has repeatedly said that Israel will not withdraw from Lebanon.
“We will restore security to (Israel’s) north,” he said Thursday in his first public remarks since the U.S.-Iran deal was announced. “This requires maintaining the security zone in southern Lebanon and requiring us not to leave it for as long as Israel’s security needs require.”
Hezbollah denies Israeli claims of violating the ceasefire, accuses Israel of continuing the war despite the US-Iran agreement, and says the group “remains vigilant against any aggression.”
On the Iranian side, deep distrust in Iran’s ability to reach a deal with the United States continues to cast a shadow over negotiations.
Ebrahim Azizi, chairman of Iran’s parliament’s National Security Committee, said on Saturday that “the United States’ failure to comply with Article 1 of the Memorandum of Understanding shows that the United States still lacks the will to gain the trust of the Iranian people.”
President Trump and Vice President J.D. Vance have shown increasing impatience over Israel’s attack on Lebanon this month and Israel’s hostility to the Iran memorandum.
“If I had been in the cabinet of the Israeli government, we might not have attacked our only remaining strong ally in the entire world,” Vance said this week.
“Mr. Vance isn’t trying to change the conversation about Israel in the United States. He’s trying to change the entire paradigm,” said Trita Parsi, deputy director of the Quincy Institute for Responsible State Strategy.
Israel still has many supporters in Washington, particularly in Congress, and President Trump said Friday that despite some hurtful conversations with Prime Minister Benjamin Netanyahu, “We fought very well with Israel and we have had a great relationship with Israel.”
The answer may depend on how aggressive President Trump is in pushing for a ceasefire without Netanyahu’s full buy-in.
“Lebanon remains the main spoiler in any broader understanding with Iran,” wrote Dany Sitrinowitz, director of Israel’s military intelligence agency’s Iran bureau, adding: “The central question is how far the United States is willing to go to enforce a ceasefire that both sides have different interpretations of.”
In talks with the Lebanese government, Israel has persistently demanded that Hezbollah be disarmed, but so far the Lebanese army has been unable to do so.
“The main political casualty of the Lebanon War appears to be the Lebanese government, which did not participate in ceasefire negotiations and is being weakened by the United States, Iran, Israel, and Hezbollah,” writes Emir Hokayem of the International Institute for Strategic Studies.
“Not surprisingly, it is highly problematic and with long-term consequences. While Iran succeeded in linking Lebanon and Hormuz, Israel’s foolish military-only strategy backfired,” Hokayem wrote in X.
