Lebanese businessman Anis Rubeiz has lived through conflict and crisis in his country but now sees no hope as all-out war between Israel and Hezbollah appears closer than ever.

"Everything is collapsing around us," said Rubeiz, 55, in Beirut's Christian-majority Ashrafieh district, criticising what he said were attempts to drag Lebanon into a war it could do without.

Lebanon is crushed by a five-year economic collapse and paralysed by a longstanding political deadlock.

An Israeli strike on Beirut's southern suburbs on Thursday killed the head of Hezbollah's drone unit, the militant group and the Israeli military said.

The Iran-backed Hezbollah said in a statement that the strike killed Mohammed Srur, born in 1973.

The Israeli military earlier said in a statement that its fighter jets had "targeted and eliminated" Srur, identifying him as "the commander of Hezbollah's air unit".

It was the fourth attack in a week targeting Hezbollah commanders in the densely populated area, one of the group's strongholds.

Top Israeli officials on Thursday rejected a US-backed proposal for a ceasefire with Hezbollah, even as Washington insisted the truce plan had been "coordinated" with Israel.

The United States and allies issued a joint call for a 21-day halt in fighting in Lebanon, where Hezbollah is based, after Israeli air strikes targeting the Iran-backed group killed hundreds and displaced tens of thousands this week.

Israel on Thursday rejected a push led by its key backer the United States for a 21-day ceasefire in Lebanon, vowing to keep fighting Hezbollah militants "until victory".

Israeli bombing of Iran-backed Hezbollah strongholds around Lebanon has killed hundreds of people this week, while the militant group has retaliated with rocket barrages.

The US and French leaders pressed jointly Wednesday for an immediate 21-day ceasefire in Lebanon, in a call joined by allies as the death toll mounts from Israeli strikes on Hezbollah.

Presidents Joe Biden and Emmanuel Macron met on the sidelines of the UN General Assembly in New York as they voiced fears that the conflict, after a year of bloodshed in Gaza, would escalate into a full-blown regional war.

US President Joe Biden warned Wednesday of the possibility of an "all-out war" in the Middle East but said he was hopeful a settlement was still achievable for the conflict-torn region.

Biden's comments as he appeared on ABC chat show "The View" came as Israel put troops on alert for possible entry into Lebanon and the war in Gaza grinds on.

"An all-out war is possible," Biden said when asked about the situation. "What I think is, also, the opportunity is still in play to have a settlement that could fundamentally change the whole region."

Israel's new UN ambassador accused the global body of pummelling his nation with unfair and disproportionate criticism since the October 7 onslaught, leaving the country feeling betrayed.

Israel has for decades accused various UN bodies of bias against it -- something they deny.

"We feel that the UN has betrayed Israel," ambassador Daniel Meron told AFP in an interview on Tuesday as the fighting with Hamas in Gaza and Lebanon's Hezbollah has increased fears of a wider Mideast conflict.

As Israeli bombs flattened buildings and sent smoke billowing skywards over Lebanon this week, Gazans looked on with both empathy and fear over how the widening war might affect them.

Israel carried out a third day of air strikes against Lebanon on Wednesday, saying it was targeting weapons caches and infrastructure belonging to the Lebanon-based Hezbollah group.

In a dramatic escalation after nearly a year of cross-border violence, Israeli air raids on Monday killed at least 558 people in Lebanon in the country's deadliest day since the 1975-1990 civil war.

Fadi, a type of rocket used for the first time by Lebanese militant group Hezbollah against Israel, has more explosive power and range than rockets deployed previously, but lacks precision, experts say.

"In an initial response" to the explosions of pagers and two-way radios, Hezbollah on Sunday said it had "bombed the Rafael military industry complexes" in northern Israel with "dozens" of Katyusha, Fadi-1 and Fadi-2 rockets.

International calls for restraint mounted Wednesday after Israel's army chief told soldiers to prepare for a possible ground offensive against Hezbollah in Lebanon amid fears of all-out war in the Middle East.

Prime Minister Benjamin Netanyahu vowed that Israel's military operations against the Iranian-backed militia would not stop until northern residents displaced by cross-border clashes could safely return to their homes.