“It doesn’t look like something is imminent,” the Pentagon’s deputy press secretary Sabrina Singh told journalists, referring to a possible Israeli incursion.

Israel’s warnings came after Hezbollah said it had targeted Israel’s Mossad spy agency headquarters on Tel Aviv’s outskirts – the first time it has fired a ballistic missile in almost a year of cross-border clashes sparked by the Gaza war.

Lebanon said Israeli strikes killed 51 people and injured 223.

The Israeli military said it hit more than 2000 Hezbollah targets over the past three days, including 60 Hezbollah intelligence sites.

In Washington, President Biden warned of the possibility of “all-out war” after Israel’s troops were put on alert for a possible ground operation.

“An all-out war is possible,” Biden told broadcaster ABC.

“What I think is, also, the opportunity is still in play to have a settlement that could fundamentally change the whole region.”

Biden added there was a “possibility” of a Lebanon ceasefire, but “I don’t want to exaggerate it”.

Cross-border clashes intensified after Israeli raids on Monday killed at least 558 people in the deadliest day of violence in Lebanon since its 1975-90 civil war.

Nour Hamad, a 22-year-old student in the eastern Lebanese city of Baalbek, described living “in a state of terror” all week.

“We spent four or five days without sleep, not knowing if we will wake up in the morning,” she said.

In Tel Aviv, sirens sounded following Hezbollah’s unprecedented missile launch at dawn.

Tel Aviv resident Hedva Fadlon, 61, told AFP: “The situation is difficult. We feel the pressure and the tension … I don’t think anyone in the world would like to live like this.”

The Israeli military said hundreds of targets had been struck across Lebanon on Wednesday.

“Fighter jets struck 60 terrorist targets belonging to Hezbollah’s intelligence directorate,” the army said.

It said two reserve brigades were being called up “for operational missions in the northern arena”, adding this would “enable the continuation of combat against the Hezbollah terrorist organisation”.

The pro-Iran Islamic Resistance in Iraq group said it attacked Israel’s Red Sea port of Eilat on Wednesday as another group urged more attacks amid soaring tensions over Gaza and Lebanon.

Israel’s military said it intercepted a drone approaching Eilat and that another fell in the area. It reported two minor injuries.

Defiant Netanyahu

The UN Security Council said it would hold an emergency meeting on the crisis in New York on Wednesday, as UN chief Antonio Guterres warned the situation was critical.

“We should all be alarmed by the escalation. Lebanon is at the brink,” he said.

The UN’s International Organization for Migration said 90,000 people had been displaced in Lebanon so far this week.

Among them, “many of the more than 111,000 people displaced since October … are likely to have been secondarily displaced”, said the UN’s Office for the Coordination of Humanitarian Affairs.

Netanyahu delayed his departure for New York until Thursday, when he too is due to speak at the UN General Assembly.

“We are striking Hezbollah with blows it never imagined. We are doing this with full force, we are doing this with guile. One thing I promise you: we will not rest until they return home”, Netanyahu said Wednesday in a statement.

The veteran right-wing Israeli leader has been accused by critics of stalling in Gaza ceasefire negotiations and prolonging the war to appease far-right coalition partners.

Iran, Hezbollah’s main backer, condemned Israel’s raids, with supreme leader Ayatollah Ali Khamenei saying the recent killing of Hezbollah commanders would not crush the group.

“Some of the effective and valuable forces of Hezbollah were martyred, which undoubtedly caused damage to Hezbollah, but this was not the sort of damage that could bring the group to its knees,” he said.

Elusive ceasefire

While the Israel-Lebanon border has seen near-daily clashes for a year, the violence escalated dramatically last week, when coordinated communications device blasts that Hezbollah blamed on Israel killed 39 people and wounded almost 3000.

Then Israel carried out an air strike on Hezbollah’s south Beirut stronghold, killing a top military commander and other fighters and civilians.

At the Lebanese Red Cross HQ in Beirut, people waited to donate blood, with Jad Assi, 39, telling AFP: “Given the crisis we’re currently experiencing, donating blood is the least I can do to show solidarity with my fellow Lebanese.”

Efforts to end the war in Gaza, which analysts say are key to stopping the escalation in Lebanon, have yet to make progress.

The war in Gaza began with Hamas’s October 7 attack on Israel, which resulted in the deaths of 1205 people, mostly civilians, according to an AFP tally based on Israeli official figures that include hostages killed in captivity.

Of the 251 hostages seized by militants, 97 are still held in Gaza, including 33 the Israeli military says are dead.

Israel’s retaliatory military offensive has killed at least 41,495 people in Gaza, most of them civilians, according to figures provided by the Hamas-run territory’s health ministry. The UN has described the figures as reliable.