A large explosion ripped through the densely packed Jabalia camp before nightfall, tearing facades off nearby buildings and leaving a deep, debris-littered crater.
Wails filled the air as hundreds of bystanders and volunteers clawed at concrete blocks and twisted metal looking for survivors.
AFP witnessed at least 47 corpses being recovered.
Horrified resident Ragheb Aqal, 41, likened the explosion to “an earthquake” and spoke of seeing “homes buried under the rubble and body parts and martyrs and wounded in huge numbers”.
Israel said its warplanes had struck a “vast” tunnel complex at the site, killing “many Hamas terrorists”, including local battalion commander Ibrahim Biari.
Military spokesman Jonathan Conricus described Biari as “pivotal in the planning and execution” of Hamas raids into Israel last month that killed 1,400 people, most of them civilians.
Israel’s leaders have vowed to “crush” Hamas in retribution for the worst attack in the country’s history.
But Tuesday’s strike is sure to fuel anger at Israel’s prosecution of the war, and the toll on Palestinian civilians.
Gaza’s Hamas-run health ministry denounced the incident as “a heinous Israeli massacre” and said an initial toll of 50 dead and 150 wounded was sure to rise.
The ministry claims that in three-plus weeks of Israeli bombing has killed more than 8,500 people in Gaza, two-thirds of them women and children.
Earlier, Bolivia had said it was severing diplomatic ties with Israel as a “repudiation and condemnation” of the Gaza offensive.
And Qatar warned that expanded strikes would “undermine mediation and de-escalation efforts”.
Doha hosts several senior Hamas officials and is a key channel in trying to secure the release of some 240 hostages believed to have been taken by Palestinian militants on October 7.
Saudi Arabia also criticised the strike, with its foreign ministry issuing a statement saying it condemned “in the strongest terms possible the inhumane targeting by the Israeli occupation forces of the Jabalia refugee camp”.
But there is little sign of the conflict abating.
As the aerial war continued, Israel said two soldiers were killed as troops engaged in “fierce battles” with Hamas militants “deep inside the Gaza Strip”
Hamas’s armed wing, the Ezzedine al-Qassam Brigades, has vowed to turn Gaza into a “graveyard” for invading forces.
– No ceasefire –
Aid groups and the United Nations warned time is running out for many of the territory’s 2.4 million people denied access to food, water, fuel and medicine.
Surgeons are conducting amputations on hospital floors without anaesthetic, and children are forced to drink salty water, said Jean-Francois Corty, vice-president of Medecins du Monde, which has 20 staff on the ground.
The Palestinian telecommunications agency said Wednesday that phone and internet services had “been completely cut off in Gaza”, the second such blackout in a week.
Israel’s Prime Minister Benjamin Netanyahu has dismissed international calls for a humanitarian ceasefire.
He said they amount to “a call for Israel to surrender to Hamas, to surrender to terrorism, to surrender to barbarism”.
“This will not happen,” he said.
Israeli officials said that 70 trucks with aid were allowed to enter Gaza from Egypt on Tuesday.
That is one of the biggest flows since a US-brokered deal was reached, but much less than humanitarian groups say is needed.
Israel fears that food, water, and medicine coming into Gaza could be diverted to Hamas, or that aid shipments could conceal arms or other supplies.
As a result, Israeli security personnel carry out stringent inspections that have slowed the flow of aid to a trickle.
Sources in Cairo said the Rafah crossing would soon be open to allow wounded Palestinians to get treatment.
– ‘No words’ –
As Israel steps up its assault on Gaza, the families of hostages are struggling with an unbearable wait for news of relatives thought to be held in the labyrinth of tunnels deep below Gaza.
“It’s really hell. There are no words to express this,” said Hadas Kalderon as she walked past the blackened homes of kibbutz Nir Oz.
There gunmen killed her mother and niece and kidnapped her 12-year-old son and 16-year-old daughter.
“I don’t have any control and knowledge about army actions, I just know my children are still there in the middle of a war,” said the 56-year-old.
Israelis also face a daily barrage of aerial attacks from Hamas and other Iran-backed groups around the Middle East.
Yemen’s Huthi rebels said they had “launched a large batch of ballistic missiles… and a large number of armed aircraft” towards Israel on Tuesday.
Israel’s military said a “hostile aircraft intrusion” had set off warning sirens in Eilat, its Red Sea resort and a surface-to-surface missile was “successfully intercepted.”
In the north, Israel has traded near-daily fire with Lebanon’s Iran-backed Hezbollah movement.