Israel-Hezbollah escalation: flare-up or all-out war?

Despite a flare-up in violence between Israel and Hezbollah on Sunday, both sides appeared to show restraint, averting all-out war amid 10 months of clashes on the Israel-Lebanon border.

AFP looks at what happened and whether the chance of a broader regional conflict still looms as the Gaza war grinds on.

- What happened? -

Hezbollah had vowed to respond to an Israeli strike on Beirut's southern suburbs last month that killed the group's senior commander Fouad Shukur.

The Iran-backed group has traded near daily fire with Israeli forces in support of ally Hamas since the Palestinian militant group's October 7 attack on Israel sparked the Gaza war.

On Sunday, the Israeli military said it launched air strikes on Hezbollah targets "that posed an imminent threat," with around 100 fighter jets striking more than 270 targets, "90 percent" of which "were short-range rockets aimed at northern Israel."

Hezbollah chief Sayyed Hassan Nasrallah said the Israeli strikes came half an hour before his group launched more than 300 Katyusha rockets at 11 Israeli military sites, and that drones then targeted deeper inside Israel, in response to Shukur's killing.

The flare-up lasted several hours, with relatively limited damage reported on both sides, and Lebanon's National News Agency saying most of the Israeli strikes targeted open areas.

Nasrallah said his group's "main target" was Israel's Glilot military intelligence base near Tel Aviv. An Israeli military spokesperson told AFP "there were no hits at the Glilot base."

Three deaths were reported in Lebanon on Sunday -- two Hezbollah fighters and another from its ally, the Amal Movement.

An Israeli navy soldier was also killed. An official told AFP an Israeli air-defense interceptor may have hit their boat.

Since the flare-up, the regular cross-border exchanges have resumed.

- Restraint? -

A Western diplomat, requesting anonymity because the matter is sensitive, said both sides "showed restraint," and that Hezbollah's attack "did not spark a large (Israeli) response."

"Diplomatic pressure contributed to avoiding a broader conflagration," the diplomat based in Beirut told AFP, noting however that cross-border violence could still further deteriorate.

Lina Khatib, an associate fellow at Chatham House, said Hezbollah wanted to "save face" by calling its attack a success, while ensuring it "did not drag Lebanon into a repeat" of the group's devastating 2006 war with Israel.

"Hezbollah is feeling pressured to retain its credibility as a Hamas ally," she said.

"But its ultimate goal in this conflict is self-preservation, it is therefore using propaganda in lieu of the kind of military action that would spark all-out war," she told AFP.

Michael Young from the Carnegie Middle East Center said in a report that "both sides were trying to control the narrative" around Sunday's escalation.

Israel's claim of pre-emptive action "gave it the latitude to avoid a major escalation in Lebanon," while Hezbollah has "pushed hard against" claims Israel thwarted its attack, he added.

- Wider war averted? -

Israeli political analyst Michael Horowitz said all-out war was "not inevitable."

"The military option... is bad because Israel cannot rapidly defeat Hezbollah," which "has an arsenal of missiles that is much more substantial than Hamas'," Horowitz told AFP in Jerusalem.

"The diplomatic option is bad because... it has never worked," he added.

A source close to Hezbollah said the group did not want a regional war, and that its retaliation aimed to deter an "escalatory" Israel from starting a broader conflict.

Nasrallah said his group waited before responding to Shukur's killing "to give a chance" to Gaza ceasefire talks because "our main goal... is to stop the (Israeli) aggression" but there had been "no point in delaying any longer."

He appeared to suggest his group's retaliation was over, while Prime Minister Benjamin Netanyahu said Israel's strikes were "not the final word" in the campaign against Hezbollah.

The risk of a regional war extends beyond the Lebanon-Israel border, with Iran and allied armed groups threatening to retaliate to strikes blamed on Israel.

Yemen's Houthi rebels have warned their response to an Israeli attack on the port of Hodeida last month "is definitely coming."

Iran also has vowed to respond an attack last month in Tehran, blamed on Israel, that killed Hamas political leader Ismail Haniyeh.

Iranian Foreign Minister Abbas Araghchi posted on X late Sunday that Tehran's response would be "definitive, and will be measured and well calculated."

"We do not fear escalation, yet do not seek it -- unlike Israel," he added.