JOHN YANG: Good evening.

I'm John Yang.

While keeping up its bombardment of Hezbollah in Lebanon, Israel struck another Iranian-backed militant group today targeting Houthi fighters in Yemen.

Israeli officials said it was in retaliation for Houthi missiles fired at Israel, but Israel's main focus remains Hezbollah striking dozens of targets today, including rocket launchers and buildings said to be storing weapons.

JOHN YANG (voice-over): Days after the massive Israeli strike that killed Hassan Nasrallah, smoke still rises from the rubble of Hezbollah's headquarters in southern Beirut, a fitting image for what Israel has done to the militant group's top command.

Today, Hezbollah confirmed the death of Nabil Kaouk, Deputy Head of its Central Council, the seventh top official Israel, was killed in a little more than a week.

Israel's targets today included two buildings near Sidon on the Mediterranean coast.

Lebanese health officials said at least 24 people were killed.

Meanwhile, Israeli defenses intercepted most of the rockets and missiles Hezbollah fired at Israel.

Across Lebanon, hundreds of thousands of people have fled their homes, some camping out on streets, others seeking refuge in a parking lot.

The Lebanese government estimates that about a quarter of a million are in shelters.

In Beirut, some residents, like Ayman feel lost.

AYMEN, Displaced Resident (through translator): The future of Lebanon is in God's hands now nothing is clear.

Look at us.

We are sleeping in the streets.

That is how our life is now.

JOHN YANG (voice-over): Others, like Francoise are defiant.

FRANCOISE AZORI, Beirut Resident (through translator): You won't be able to destroy us.

Whatever you do, however much you bomb, however much you displace people, we will stay here.

JOHN YANG (voice-over): Inside, Mohamed says he thinks about evening the score.

MOHAMED FARHAT ABU RASHAD, Sidon Resident (through translator): The war will continue, God willing, until we take our revenge for the Gazan people and the displaced people in Lebanon.

JOHN YANG (voice-over): On ABC's This Week, White House National Security Council Spokesman John Kirby said the United States is prepared for any response.

JOHN KIRBY, White House National Security Council Spokesman: Well, their rhetoric certainly suggests they're going to try to do something.

I mean, just coming out of Tehran, but we don't really know.

We're watching this very, very closely to see how, if and how Hezbollah and or Iran may react, as well as the militia groups in Iraq and Syria.

JOHN YANG: Late today, President Biden said all out war in the Middle East has to be avoided.

He said he would soon talk with Israeli Prime Minister Benjamin Netanyahu.

Special correspondent Leila Molana-Allen is in Beirut tonight.

Leila, Israel seems to be just striking at will for the past several days.

What's this doing to the Lebanese people?

LEILA MOLANA-ALLEN: The feeling amongst the Lebanese people is one of terror.

There's always a sense here that a hope that things won't be as bad as they seem could get but those chances of this not becoming all out war in the Middle East seemed to be dwindling by the second arriving from Beirut airport, which is normally an incredibly lit up area with busy streets, everything was dark, all the lights out.

Really somber, quiet.

People are incredibly fearful of what's to come.

Because, of course, the biggest event was the confirmation yesterday by Hezbollah that the head of Hezbollah, Hassan Nasrallah, was killed by Israel in that enormous strike in the southern suburbs of Beirut on Friday, and since then, people now feel all cards are off the table.

Anything could happen, and it hasn't stopped since today, 100 people were injured, more than 50 killed in further strikes across the country.

People are terrified, many of them flooding to the airport, but many also returning to Lebanon, saying they're going to stay here through the war.

They've done it before, and they can do it again.

Of course, the last time we saw this on this level was in 2006 that was a 33-day war.

More than 1,000 people were killed, but already, three quarters that number have been killed in just the past week in Lebanon.

JOHN YANG: The target of all this is not these, the Lebanese people, but it's Hezbollah.

How did the people view Hezbollah?

Do they stand with it, or are they angry that they brought this on them?

LEILA MOLANA-ALLEN: This is a lot more complicated than the way that it's often presented.

So of course, Hezbollah is not all of the Lebanese people.

The majority of the Lebanese people do not support Hezbollah.

Within those who do support Hezbollah, Hezbollah is not just a terrorist organization, as it's designated by Western nations.

It's not just a military organization.

It's also a political one.

It forms part of the government here.

It runs social services, hospitals, schools.

So many people who live in Hezbollah areas, while they might not like some of the foreign political actions that Hezbollah takes, they are looked after them on a daily basis.

They are the people who are essentially their local government.

And beyond that, even though there are many Lebanese who feel that Hezbollah are responsible for what's happening now, have brought this on the country by refusing to lay down their arms since the end of the Civil War and by repeatedly attacking Israel, they still do feel that Israel is the aggressor here.

This is not a case where anyone agrees with what Israel is doing.

The Israeli army, the IDF, they say that they are carrying out only precision strikes, but we are seeing so many civilians killed.

These are very, very densely packed residential areas.

Hezbollah militants live amongst these people, so it's impossible to separate the two out.

And everyone here feels that Israel is the aggressor in this and is being indiscriminate in its attacks.

JOHN YANG: Of course, there was an all out war between Lebanon Israel within the past two decades is, does that memory affect people?

LEILA MOLANA-ALLEN: That affects people hugely.

People my age here were in high school in 2006.

I remember those days.

I had Lebanese friends who were getting on to aircraft carriers from the port.

Because, of course, the first thing that the Israeli army did was hit the airport, takeout Beirut airport.

They haven't done that so far, but that memory is very fresh in people's minds.

A lot of young people died.

Half of the capital was decimated, as was the whole of the South.

So people remember very freshly, people who are just in their 20s and 30s, how terrible that war was, how long it took to rebuild, and they're absolutely terrified of that happening again.

And of course, the difference this time is that the last time there was a war, Lebanon was on a high it had rebuilt after the Civil War.

The economy was doing better.

There was lots of building work going on.

They had more money.

They were able to rebuild without too much trouble.

Or it did take a while.

This time round, Lebanon is ruling from years of crisis, the third biggest financial crash in history.

People -- there's huge unemployment.

Many people have left the country to try and find jobs.

Those left here are the most desperate, the most vulnerable, and they really can't cope with this.

We're seeing hundreds of thousands of people now either displaced or fearing that they will have to leave their homes.

They really don't have anywhere to go, and they don't have the money to support themselves, and they don't have a government that can support them either.

JOHN YANG: Israel has really shown its capability throughout this, the ability to infiltrate the supply chain with the pagers, to strike Hezbollah's leadership at will, has this in any way changed the balance of power in the region.

LEILA MOLANA-ALLEN: It absolutely has.

I mean, what's become very clear, not just in the past week, but over the past few months, is that if anybody ever underestimated Israel, they were fools to do so.

At the beginning of the war with Gaza on the eighth of October last year, many people were saying all Israel has to be very careful.

They can't afford to split their forces if they're thinking about the northern border with Lebanon as well.

They're now not just thinking about Gaza and the northern border with Lebanon as well as the deployments they have in the West Bank.

They've also been striking the Houthis in Yemen.

They're threatening Iran as well, and they've shown that they can do it over the past few months what they've achieved, taking out the leader of Hamas in Tehran on foreign soil, when he was attending the inauguration of the new president in Iran, being able to take out Hassan Nasrallah, who is nothing short of a myth, really.

I mean, this man, it's difficult to overstate how important his legend is in this part of the world.

People thought he was a ghost that you would never be able to get hold of him.

He lived underground.

He never appeared in public.

He was able to move seamlessly, and somehow they managed to get him the level of intelligence that Israel must have to be able to infiltrate it to the point where they could kill Hassan Hasrallah.

Where they could take out all these different leaders, and where they were able to tackle the pages and the walkie talkie smuggling explosives into the homes of thousands of Hezbollah operatives.

It's very clear that they have been working with a huge network of intelligence, that they've infiltrated every level of this sheer network across the region, and people now feel but there's more to come than not finished yet.

JOHN YANG: More to come.

Leila Molana-Allen in Beirut tonight.

Thank you very much.

LEILA MOLANA-ALLEN: Thanks, John.