Israeli tanks have been active in Gaza for at least four days following weeks of air bombardments in retaliation for an attack by Palestinian Hamas militants on mostly Israeli civilians on Oct. 7 and the taking of more than 200 hostages.

An Israel Defense Forces (IDF) statement said the strike by fighter jets on Jabalia, Gaza's largest refugee camp, had killed Ibrahim Biari.

"He was very important, I would say even pivotal in the planning and the execution of the October 7 attack against Israel from the northeastern parts of the Gaza Strip," said IDF spokesperson Lieutenant Colonel Jonathan Conricus.

Dozens of Hamas combatants were in the same underground tunnel complex as Biari and were also killed when it collapsed in the attack, Conricus said.

"And I understand that is also the reason why there are many reports of collateral damage and non-combatant casualties. We're looking into those as well," he said.

Palestinian health officials said at least 50 Palestinians were killed in the refugee camp and 150 wounded. Hamas spokesperson Hazem Qassem denied any senior commander was there and called the claim an Israeli pretext for killing civilians.

A Hamas statement said there were 400 dead and injured in Jabalia, which houses families of refugees from wars with Israel dating back to 1948. Reuters could not independently verify the reported casualty figures.

The blast left large craters surrounded by wrecked concrete buildings.

Israel has sent repeated warnings to Gaza residents to evacuate northern areas and while many have gone south, many have not.

PUBLIC HEALTH CRISIS ENGULFS GAZA

Power generators in al Shifa Medical complex and the Indonesian Hospital in Gaza will stop in hours, Ashraf Al-Qidra, spokesperson for the health ministry in Gaza said late on Tuesday. He called on petrol stations owners in the enclave to urgently feed the two hospitals with fuel if possible.

In Washington, a group of anti-war protesters raised red-stained hands to interrupt a hearing in Congress on providing more aid to Israel. They shouted slogans including, "Ceasefire now!" "Protect the children of Gaza!" and "Stop funding genocide." Capitol police removed them from the room.

U.N. and other aid officials said civilians in the besieged Palestinian enclave were engulfed by a public health catastrophe, with hospitals struggling to treat casualties as electricity supplies petered out.

After the attack on Jabalia, dozens of bodies lay shrouded in white, lined up against the side of the Indonesian Hospital, footage obtained by Reuters showed.

Juggling dwindling supplies of medicines, power cuts and air or artillery strikes that have shaken hospital buildings, surgeons in Gaza have worked night and day trying to save a constant stream of patients.

"We take it an hour at a time because we don't know when we will be receiving patients. Several times we've had to set up surgical spaces in the corridors and even sometimes in the hospital waiting areas," Dr. Mohammed al-Run said.

Iran-backed Hamas has told mediators it will release some foreign captives in coming days, Abu Ubaida, the spokesperson of the group's armed wing, al-Qassam Brigades, said in a video on the Telegram app on Tuesday. He gave no further details on the number of captives or their nationalities.

Meanwhile, Israeli families of victims of the Oct. 7 attack appealed to the International Criminal Court on Tuesday to order an investigation into the killings and abductions. Israel is not a member of the Hague-based court and refuses to recognise its jurisdiction.

"PROGRESS" ON SAFE PASSAGE FOR FOREIGNERS

The United States has made "real progress" in the last few hours in negotiations to secure a safe passage for Americans and other foreign nationals who wish to leave Gaza, U.S. State Department spokesperson Matthew Miller said.

U.S. Secretary of State Antony Blinken will visit Israel on Friday for meetings with members of the government there and then make other stops in the region, the department said.

The U.S., Qatar and Egypt have been working to open the Rafah crossing into Egypt to allow people to come and go.

Egyptian authorities would allow 81 Gazans who were severely wounded in the weeks of bombardment to enter Egypt on Wednesday to complete treatment, the Palestinian border authority said.

Israeli Prime Minister Benjamin Netanyahu dismissed international calls for a "humanitarian pause" in fighting to enable emergency aid deliveries to civilians suffering from critical shortages of food, medicine, drinking water and fuel.

He has vowed to press ahead with plans to annihilate Hamas after several inconclusive wars dating back to the militant group's 2007 takeover of Gaza.