JOHN YANG: Good evening.

I'm John Yang.

Even before Israel launches what's promised to be a massive assault on Gaza.

Palestinian officials say this week old war is already the deadliest Israeli-Palestinian conflict.

Gaza's health ministry says at least 2,600 Palestinians have been killed as Israel retaliates against Hamas for their brutal assault last week that left more than 1400 Israelis dead.

There is a flurry of activity in the region.

Secretary of State Antony Blinken is headed back to Israel on Monday.

The State Department said it would evacuate us citizens from Israel tomorrow by boat and National Security Adviser Jake Sullivan said President Biden will ask Congress for a $2 billion weapons package for both Israel and Ukraine.

Special correspondent Leila Molana-Allen has our report tonight and we want to warn you that some of the images may be disturbing.

LEILA MOLANA-ALLEN: In Israel, the hordes of tanks heading south are a preview of what's likely to come.

Israel's defense minister promised a punishing assault on the Gaza Strip.

YOAV GALLANT, Defense Minister, Israel (through translator): It will be a mighty war, it will be a deadly war.

It will be a precise war and it will be a war that will change the situation forever.

LEILA MOLANA-ALLEN: Since last night, we've been seeing a huge mastering of the Israel Defense Forces above and along Israel's southern border with Gaza, thousands of military vehicles, hundreds of thousands of troops coming here and the mass movement suggests that a ground invasion into Gaza is imminent.

As the wall staging ramps up, Hamas and the Israel Defense Forces continued to exchange rocket fire.

The southern Israeli town of Sderot, little more than a mile from Gaza continued to be a target for Hamas rockets.

Squaring a broader evacuation.

RAYA SCWARTZ, Resident of Sderot: We leave Sderot because the situation is very dangerous here.

LEILA MOLANA-ALLEN: And Israeli airstrikes continued to pummel Gaza.

Israel reported striking more than 100 military targets overnight, but those targets are surrounded by civilians.

In Gaza City overwhelmed emergency crews are using ice cream trucks to store bodies.

The morgues are all full.

Hospitals are days away from running out of fuel.

Doctors at the Kamal Edwan Hospital in northern Gaza had been told to evacuate.

But Dr. Hussam Abu Safiya says that would endanger children and babies in their care.

DR. HUSSAM ABU SAFIYA, Kamal Edwan Hospital (through translator): As you can see, this section is full of newborn cases.

There's no humanity in the world that can agree to disconnecting these children from this equipment and transferring them to another location LEILA MOLANA-ALLEN: Near the Rafah border crossing from Egypt to Gaza, aid convoys can't get in and foreigners still can't get out.

The U.S. has been trying to broker a deal.

On ABC This Week, National Security Adviser Jake Sullivan said evacuating American passport holders is a priority.

JAKE SULLIVAN, National Security Adviser: That has been difficult because of the ongoing operations.

And frankly, because Hamas has intervened in some cases, to make it hard for Palestinians, Palestinian-Americans and others to be able to travel to the border crossing and get through.

LEILA MOLANA-ALLEN: The U.S. is sending a second aircraft carrier strike group the USS Eisenhower to the eastern Mediterranean to help deter hostilities against Israel.

And on Israel's northern border with Lebanon, tensions have boiled over.

IDF forces responded to rocket fire from Hezbollah with shelling of their own.

And we're really seeing this building conflict start to escalate on multiple fronts.

Syria also fired into Israel today.

And the Israelis are putting on a massive show of force as they prepare for a war that they might have to fight on multiple borders.

John.

JOHN YANG: Laila did really terrific reporting.

I understand you were at the border between Israel and Gaza earlier today.

Tell us what you saw.

LEILA MOLANA-ALLEN: What I saw on the border today was really like nothing I've not seen in any war.

And I was actually speaking to a military expert today who said the same, the number of tanks rolling down being carried, mustering all across the highway, buses full of soldiers being stepped down as well.

I mean, the assembly is quite incredible.

The number of armored vehicles, jets flying through the air, drones flying everywhere.

This is a huge operation, and they're all getting ready for what they think is going to be for them a war of existence.

We're seeing these different conflicts getting involved, of course, we've got Gaza and the focus here is going across the border into Gaza, where they want to defeat Hamas, but on the other borders as well.

Lebanon, Syria, there are serious concerns that this could turn into a regional conflict and they are showing that they're ready.

JOHN YANG: Leila Molana-Allen in Tel Aviv tonight.

Thank you very much, and please stay safe.

LEILA MOLANA-ALLEN: Thank you, John.