AMNA NAWAZ: Watching the latest developments for us here is our foreign affairs and defense correspondent, Nick Schifrin.

So, Nick, let's begin with what Leila mentioned there about the U.S. deployment of an air defense system to Israel.

Tell us about that and how significant that is.

NICK SCHIFRIN: This is the first time, Amna, that U.S. forces will deploy into Israel since the October 7 attack.

About 100 service members will arrive with a THAAD battery.

That is the Terminal High Altitude Area Defense.

It defends against ballistic missiles, so it would be used alongside Israeli missile defense against Iranian attacks.

That's two weeks after 180 Iranian ballistic missiles really caused no damage, but, as you can see there, it got through U.S. and Israeli air defense.

So, THAAD would help defend Israel should Iran launch another attack to a response what we could expect any moment, which is an Israeli strike on Iran.

U.S. officials tell me that they continue to urge Israel not to attack nuclear energy sites, but instead to target military intelligence sites.

U.S. officials tell me they believe Israel's leadership is listening, but there's no guarantee about their final decision.

As for that THAAD battery, President Biden said it would be to -- quote -- "protect Israel."

But there are downsides.

The U.S. Army only has seven of them all over the world.

It's very expensive.

And there's no quick way to replenish missiles if U.S. troops do use them to help protect Israel.

AMNA NAWAZ: Let me ask you too about Gaza and Leila's reporting there.

We saw those horrific images from Deir al Balah.

We have seen now Israel intensify its assault in Northern Gaza.

The U.N. has condemned the large number of civilian casualties in recent days.

What's behind that Israeli intensification?

NICK SCHIFRIN: So, as for the strike itself, a National Security Council spokesperson released a statement this afternoon saying -- quote -- "What happened there is horrifying."

An Israeli Defense Forces statement says that they targeted -- quote -- "terrorists" operating inside a command-and-control center in a parking lot full of displaced persons next to the Al-Aqsa Hospital, and the fire was most likely caused by secondary explosions and that they are reviewing the incident.

Amna, you and I have talked about for the last year.

The Israeli rules of engagement allow Israel to target what it calls senior Hamas leaders or Hamas fighters even if surrounded by civilians, even if surrounded by women and children.

And Israel calls that Hamas using civilians as human shields.

But a U.N. report, as you were just suggesting, calls out Israel for -- quote -- "its concerted policy to destroy Gaza's health care system."

And that airstrike is part of a larger Israeli effort in Northern Gaza.

Israeli military has reentered Northern Gaza with tanks, issued evacuation orders for some 400,000 people as Hamas fighters have regrouped.

U.S. officials say that Hamas fighters have only regrouped because Israel has no strategy for the day after.

The U.N. also says that Israel's new campaign has blocked all aid into Northern Gaza since October the 1st, leading Israel's military to deny a plan that's now been made public that's been known as a retired general's plan to starve out Northern Gaza to create a permanent military zone.

Today, Israel published these images, some 40 trucks arriving into Northern Gaza.

U.S. officials have been pushing Israel to allow more aid to go in and warning that, if more aid didn't go in, the U.S. could declare Israel was blocking aid officially, and that could require U.S. law suspending some arms sales to Israel.

But bottom line is, that remains a threat, and Gazans say nowhere is safe.

AMNA NAWAZ: And quickly, Nick, before you go, on Lebanon, what is the Israeli goal there?

NICK SCHIFRIN: Israeli officials continue to say that they are trying to get some 60,000 people displaced from Northern Israel back into their homes.

And to do so, they have to go into Southern Lebanon to get rid of Hezbollah fighters and tunnels.

We saw this video released today, Israeli forces releasing what it said was a Hezbollah command-and-control bunker of weapons, food, motorcycles for an October 7-style attack.

But the bottom line is, the routes that Israel would need to go in with armored vehicles run right through those U.N. bases.

Today, the U.S. says UNIFIL must not be harmed, that Israel's invasion needs to be -- quote - - "limited."

But the last time Israel promised a limited invasion of Lebanon, it was 1982, they stayed for 18 years.

AMNA NAWAZ: Nick Schifrin, thank you very much.

NICK SCHIFRIN: Thank you.