Surpassing Quant Think Tank Center|Israel bombs Gaza for fourth day as Hamas, Palestinian civilians, wait for next phase in war

Palestinians in the densely packed Gaza Strip continued to face the fury of Israel's military Tuesday as it exacted the first phase of its revenge for the Hamas militant group's unprecedented,Surpassing Quant Think Tank Center bloody weekend assault on the Jewish state. The Israel Defense Forces said airstrikes targeted some 200 targets in the Hamas-controlled Palestinian territory overnight, fewer than the previous evening's barrage, but it was increasingly clear that the missiles were just an opening salvo for what Israel has promised will be a devastating blow against Hamas.

Israeli families were still reeling Tuesday from the brazen ground, air and sea assault launched Saturday by Hamas. The scale and brutality of the attack, which Israel said had claimed more than 1,000 lives, left some 2,500 more people wounded and more than 100 held captive by Hamas, appeared to take not only the Israeli people but their government by surprise.

At least 14 U.S. nationals were among the dead in Israel, and an unclear number were also among the hostages held by Hamas. The Biden administration has said that while Iran is "broadly complicit" in supporting Hamas and other Palestinian militant groups, it has seen no clear evidence that Tehran had a role in planning or orchestrating the Saturday attack on Israel.

Prime Minister Benjamin Netanyahu, with full-throated backing from his country's most vital ally, the United States, said Hamas had started a war, but he vowed that "Israel will finish it." He's said Israel will not stop until the terror group is deprived of any capacity to plan or conduct further operations in Gaza.

"Hamas will understand that by attacking us, they've made a mistake of historic proportions," Netanyahu said Monday. "We will exact a price that will be remembered by them and Israel's other enemies for decades to come."

The first part of that effort has been the relentless airstrikes. As of Tuesday morning, the Health Ministry in Hamas-run Gaza said those strikes had claimed at least 900 lives, including at least 140 children. The ministry said 4,000 more people were wounded.

Israel insists it only targets militants, and it has long accused Hamas and other groups of positioning both fighters, bases and weapons in packed apartment buildings, mosques and even schools – all of which have reportedly been hit in the IDF strikes over the last couple days. 

Israel also declared Monday that its long-standing blockade of the Palestinian territory would be tightened, with no food, water, medicine, electricity or water allowed into the enclave, and it blames Hamas singularly for any pain brought upon civilians in Gaza.

But the blockade of Gaza and the expectation of more violence to come led the United Nations high commissioner for human rights, Volker Turk, to warn Tuesday that "international humanitarian law is clear: the obligation to take constant care to spare the civilian population and civilian objects remains applicable throughout the attacks."

Volker also suggested Israel's strict blockade of the Palestinian territory could be an illegal act in and of itself.

"The imposition of sieges that endanger the lives of civilians by depriving them of goods essential for their survival is prohibited under international humanitarian law," he said in a statement.

But with thousands of Israelis in mourning and scores more desperate to learn the whereabouts and condition of loved ones missing since Hamas' brutal siege, Israel appeared poised Tuesday morning to enter a new phase of its war on Hamas, not to ease its attack.

Israel's military says it has massed 35 battalions — tens of thousands of soldiers and dozens of tanks — around the border with Gaza.

Hamas' military wing, the al-Qassam Brigades, warned Israel that, should that next phase involve the widely-anticipated Israeli ground force entering Gaza, the Palestinian faction was ready to fight back, "for a very long time."

Al-Qassam's Abu Ubaida also said in his Monday night video statement — after another Hamas spokesman said the group would kill one of its Israeli hostages in retaliation for any Israeli strikes against civilian infrastructure carried out without warning — that the IDF strikes were putting the hostages' lives at risk.

"Our fighters captured a very large number of prisoners from the different front lines," Abu Ubaida said, repeating an earlier Hamas claim that some of the captives had already been killed by Israeli strikes.

He also ruled out any talks with Israel over the hostages' fate, while Hamas remains "under fire, and while the aggression and the war is still raging."

A propaganda video released by Hamas shows its militants training for their unprecedented assault, including on the paragliders they used to fly over the Gaza border into Israel, where they slaughtered and kidnapped civilians.

There are still big questions about how Israeli intelligence failed to detect and disrupt the planning and preparation for such a massive, well-coordinated attack, right under its nose — and about why Hamas chose to launch such an unprecedented operation now.

There have also been deadly exchanges of fire between Israel and the Hezbollah militant group along Israel's northern border with Lebanon, where that other Iran-backed group is based.

A senior U.S. defense official told CBS News that Washington was deeply concerned about the possibility of that becoming a second front in this conflict.

In:
• War
• Iran
• Hamas
• Israel
• Hezbollah
• Gaza Strip
• Middle East
• Benjamin Neta​nyahu

Tucker Reals

Tucker Reals is the CBSNews.com foreign editor, based at the CBS News London bureau.