It has vowed to annihilate the Hamas movement that rules Gaza in retribution for the deadliest attack on civilians in Israel's history.
And put Gaza, home to 2.3 million people, under total siege.
As well as launching by far the most powerful bombing campaign in the 75-year-old Israeli-Palestinian conflict, destroying whole neighborhoods, killing more than 1,400 Palestinians
and forcing hundreds of thousands to flee their homes.
The International Committee of the Red Cross pleaded for fuel to be allowed in to stop overwhelmed hospitals from, quote, "turning into morgues."
ICRC regional director Fabrizio Carboni:
"What's certain, is that if we can't get supplies in and if we can't distribute what we have inside Gaza, I wanted to say we are going toward a catastrophe, but we are already in the catastrophe, but here, we are going well beyond that and the humanitarian situation will become unmanageable."
U.S. Secretary of State Antony Blinken, arriving in Tel Aviv to show solidarity, told Prime Minister Benjamin Netanyahu Washington would always be by Israel's side.
Scores of Israelis gathered in Jerusalem's Mount Herzl military cemetery on Thursday to bury their dead.
According to an Israeli public broadcaster, the death toll from the Hamas attacks has passed 1,300 people. They were gunned down in their homes, on the street and at a rave.
As Israel masses tanks on Gaza's border, its next move could be a ground assault.
The head of Israel's military, Lieutenant General Herzi Halevi, said lessons would be drawn from the security failures around Gaza that enabled the Hamas attack.
