GEOFF BENNETT: As we saw in Leila's report, Defense Secretary Lloyd Austin made a quick day trip to Israel today from NATO meetings in Brussels, the second U.S.

Cabinet official in as many days to visit.

Our Nick Schifrin traveled on this whirlwind journey today with Austin and spoke with Israeli officials too.

He's back in Brussels tonight.

So, Nick, what did Secretary Austin want to convey in person with his trip to Israel?

NICK SCHIFRIN: He certainly wanted to show U.S. support to Israel, as you said, one day after Blinken did the same.

And he got an operational update on what appears to be the imminent ground invasion by Israel into Gaza.

And you can only get that in person.

We got down into the basement of the Ministry of Defense, where he received that update.

He certainly pledged his support, Geoff, but he also voiced a note of caution that was first made by President Biden.

And he said that Israel, unlike Hamas, needed to consider Gaza casual -- Gaza civilians.

LLOYD AUSTIN, U.S. Secretary of Defense: And the president also underscored that democracies like ours are stronger and more secure when we uphold the laws of war.

Terrorists like Hamas deliberately target civilians, but democracies don't.

This is a time for resolve, and not revenge, for purpose, and not panic, and for security, and not surrender.

NICK SCHIFRIN: Resolve, not revenge, a clear message to Israelis, who, when they speak to us, are using that exact word, desiring their Israeli government to -- in order to achieve that word in Gaza over the coming days.

Austin also brought up his time as the commander of the counter-ISIS mission in Iraq and Syria.

And he pointed out that, despite heavy fighting, despite ISIS fighters embedding into the civilian population, his troops were able to create humanitarian corridors for civilians.

And that is exactly what the U.S. wants to see Israel do, Geoff, in Gaza.

GEOFF BENNETT: As we mentioned, Nick, I know you spoke with Israeli officials during the course of your reporting today.

What did they tell you?

NICK SCHIFRIN: The primary thing they told us is how grateful they were for Austin's visit, for President Biden's full-throated support of Israel, and for the largest U.S. aircraft carrier in the world, the USS Ford, which is parked off of Israel right now.

They see that as an incredibly important and effective deterrent against Lebanese Hezbollah, against Iran, helping Israel avoid having to fight on two separate fronts.

The senior official told me that the common ground invasion of Gaza would not be the same as previous ground invasions.

He said -- quote -- "This is going to be something different, something out of the box," but of course, he would give no details.

But in 2014, I was reporting inside Gaza and saw how Israel really struggled to achieve its goals in what was a limited incursion back then, and the incursion expected in the coming days is going to have much greater goals than what they have done in the past, of course.

As for that evacuation order, the senior official said there was no 24-hour deadline, as the U.N. reported, but he was dismissive of any humanitarian concerns that Leila was reporting on in relation to that movement of 1.1 million Gazans to the south.

He said -- quote -- "That's Hamas' problem.

We're at war."

GEOFF BENNETT: And, Nick, you also visited a military base in Southern Israel where the U.S. is right now flying in weapons.

What did you see there?

NICK SCHIFRIN: Yes, this is the Nevatim Air Base that Secretary Austin visited a few hours ago.

It's about 40 miles east of Gaza in Israel's southern desert.

Austin walked with the deputy minister of defense.

He met with U.S. troops, and he saw the second aircraft of U.S. weapons that have arrived in Israel.

That aircraft arrived earlier today.

In total, the U.S. is sending a series of weapons, most notably, Iron Dome munitions, expecting those Hamas rockets to continue, small-diameter bombs, which are bombs designed to be more precise, and therefore cause fewer civilian casualties, what are known as the Joint Direct Attack Munition, or JDAM, kits.

Those turn older dumb bombs, so to speak, into precision-guided munitions, and -- quote -- "critical ammunition" that Israeli soldiers use.

That senior Israeli official actually told me that most of that weapons systems that are arriving are for in case a second front is opened.

And that is really the U.S. and Israeli focus right now, to try and prevent that second front from opening and trying to contain the conflict to Israel and Hamas, because U.S. officials describe a kind of nightmare scenario, not only Israel fighting on multiple fronts, but violence spilling into other countries across the region.

And that would threaten us goals, normalizing relations between Israel and Saudi Arabia and keeping the region calm.

At this point, Geoff, U.S. officials are just trying to make sure the fire doesn't spread.

GEOFF BENNETT: Nick Schifrin reporting for us tonight from Brussels.

Nick, thank you.