Israel pounded the Gaza Strip for the fifth straight day since Hamas' unprecedented attack and the death toll spiralled into the thousands, as Prime Minister Benjamin Netanyahu vowed the complete destruction of the Palestinian group.
"Every Hamas member is a dead man," the right-wing Israeli leader said, comparing it to the Islamic State group and promising: "We will crush them and destroy them as the world has destroyed Daesh."
Netanyahu earlier temporarily settled his political differences and set up an emergency government including former defence minister Benny Gantz for the duration of the crisis.
Saturday's surprise attack -- the worst in Israel's 75-year history -- has seen a total of 1,200 people killed, according to Israeli forces.
In Gaza, officials reported more than 1,000 people killed by Israel's sustained campaign of air and artillery strikes on the besieged populated Palestinian enclave, sending black smoke billowing into the sky and razing entire city blocks.
The United Nations said 11 of its staff had been killed in Gaza by Israeli strikes since Saturday, while the International Red Cross and Red Crescent societies said it had lost five of its members.
In the occupied West Bank, at least four Palestinians were killed when armed Israeli settlers attacked a town south of Nablus, taking the death toll to 29, the Palestinian health ministry said.
Israel has massed forces, tanks and other heavy armour around Gaza in its operation against what Netanyahu labelled "an attack whose savagery... we have not seen since the Holocaust".
US President Joe Biden pledged to send more munitions and military hardware to its close ally Israel and expressed revulsion at the "sheer evil" of the slaughter of civilians.
Biden also made his first call for restraint over Israel's response to the Hamas attacks, urging Israel to abide by the rules of war.
He said he had told Netanyahu it was "really important that Israel, with all the anger and frustration... they operate by the rules of war".
The crisis saw Netanyahu strike a political deal with Gantz and pledge to freeze for now his government's judicial overhaul plan that has sparked unprecedented mass protests.
Opposition leader Yair Lapid has not joined the temporary alliance, although the joint statement said a seat would be "reserved" for him in the war cabinet.
"Israel before anything else," Gantz wrote in a social media post, while the far-right National Security Minister Itamar Ben-Gvir wrote that he "welcomes the unity, now we must win".
Concern rose over the worsening humanitarian crisis in war-torn Gaza, where Israel had levelled over 1,000 buildings and imposed a total siege, cutting off water, food and energy supplies for 2.3 million people. Gaza had already been under Israeli blockade for almost 17 years prior to Saturday.
The enclave's sole power plant shut down Wednesday after running out of fuel, Gaza's electricity provider said.
More than 260,000 Gaza residents have been forced from their homes, a UN aid agency said, with secretary-general of the world body, Antonio Guterres, voicing fears of a deterioration in an already dire humanitarian situation.
The European Union called for a "humanitarian corridor" to allow civilians to flee the Israel's fifth war on the enclave in 15 years.
Arab League foreign ministers meeting in Cairo called for aid to be allowed into Gaza "immediately".
Israel appeared to be readying for a possible ground invasion of Gaza, but faces the threat of a multi-front war after also coming under rocket attack from militant groups in neighbouring Lebanon and Syria.
Israel again struck targets Wednesday in southern Lebanon, an area controlled by the Iran-backed Hezbollah.
On Wednesday evening, rocket sirens sounded across Israel's north, and the army said there was a suspected aerial "infiltration" from Lebanon. It later backtracked, blaming an "error".
Biden, who has diverted an aircraft carrier battle group to the eastern Mediterranean, has warned Israel's enemies -- state or group -- not to get involved.
He urged Iran, which has long financially and militarily backed Hamas but insists it had no involvement in Saturday's assault, to "be careful".
A first US aircraft has delivered "advanced armaments" to southern Israel's Nevatim Airbase, the Israeli army said.