While the army launched the pre-dawn raid at Gaza City's Al-Shifa hospital, the Israeli government deployed Mossad chief David Barnea to Qatar for renewed talks toward a cease-fire and hostage release deal.
Qatari and Egyptian mediators hope to pause or end the war that has devastated Gaza since the October 7 attack — even as Israeli Prime Minister Benjamin Netanyahu has doubled down on his vow to destroy Hamas.
Gaza's soaring civilian death toll, the large-scale devastation and the looming threat of famine for its 2.4 million people have hardened opposition to Israel's military campaign and siege.
A U.N.-backed food security assessment warned that half of Gazans are experiencing "catastrophic" hunger, and that "all evidence points towards a major acceleration of deaths and malnutrition."
EU foreign policy chief Josep Borrell said Israel's military campaign had turned Gaza from the world's "greatest open-air prison" into its biggest "open-air graveyard" and that Israel was using famine as a "weapon of war."
Foreign Minister Israel Katz replied that "Israel allows extensive humanitarian aid into Gaza" and told Borrell "to stop attacking Israel and recognize our right to self-defense against Hamas' crimes."
In the latest heavy battle, Israel's army raided Al-Shifa, with witnesses reporting air strikes and tanks near the complex reportedly crowded with thousands of Palestinian patients and displaced people.
The health ministry of the Hamas-run Gaza Strip said nearby residents had reported dozens of casualties who could not be helped "due to the intensity of gunfire and artillery shelling."
World Health Organization chief Tedros Adhanom Ghebreyesus said that "we are terribly worried" about the fighting which was "endangering health workers, patients and civilians."
The Israeli military told Gazans to evacuate the area amid the raid that it said was based on intelligence "indicating the use of the hospital by senior Hamas terrorists."
The army and Shin Bet security service said forces had "identified terrorist fire toward them from a number of hospital buildings" and that "the forces engaged the terrorists and identified several hits."
Israel's military dropped Arabic-language leaflets warning residents that "You are in a dangerous combat zone!" and urging them to flee the area.
The Hamas government media office condemned as a "war crime" the "storming of the Al-Shifa medical complex with tanks, drones and weapons and shooting inside."
The army previously raided Al-Shifa in November, sparking an international outcry, in an operation in which it said it found weapons in rooms in and below the hospital where it believed hostages had been held.
Israel's military said Monday that troops had been told to "avoid harm to the patients, civilians, medical staff and medical equipment," with Arabic speakers deployed.
The bloodiest ever Gaza war broke out after Hamas launched an unprecedented attack on October 7 that resulted in about 1,160 deaths in Israel, mostly civilians, according to an AFP tally based on official Israeli figures.
The Islamist militants also seized about 250 hostages, of whom Israel believes 130 remain in Gaza, including 33 who are presumed dead.
Israel has carried out a relentless bombing campaign and ground offensive that Gaza's health ministry says has killed at least 31,726 people, most of them women and children.
As the fighting flared around A-Shifa, the army announced that the number of its soldiers killed in the Gaza ground invasion launched in late October had risen to 250.
Global concern has focused on Gaza's far-southern city of Rafah, where about 1.5 million Palestinians now live in crowded shelters and tent cities near the Egyptian border.
Netanyahu's repeated warnings of a looming ground invasion have raised fears the civilians would be in the line of fire, and Israel's top ally the United States has stressed Israel must ensure civilians are "out of harm's way."
The Israeli premier on Sunday reiterated that civilians would be evacuated from Rafah before any ground attack, without detailing where to.
"Our goal in eliminating the remaining terrorist battalions in Rafah goes hand-in-hand with enabling the civilian population to leave Rafah," he said.
Efforts toward a truce and hostage release deal — which have involved US, Qatari and Egyptian mediators —were expected to resume in Qatar, following a week-long ceasefire in November.
Hamas had so far called for a complete withdrawal of Israeli forces, a demand which Netanyahu has rejected as "delusional."
A new Hamas proposal calls for an Israeli withdrawal from "all cities and populated areas" in Gaza during a six-week truce, and for vastly more aid, according to an official from the group.
It proposes a 42-day truce during which it would release about 42 hostages — each in exchange for between 20 and 50 Palestinian prisoners to be released from Israeli custody.
The exchange could include women, children, elderly and ill hostages, whereas male soldiers and the bodies of dead hostages would be returned during a later, comprehensive exchange to coincide with a full ceasefire.
Netanyahu's office said on Friday that Hamas's new proposal was "unrealistic" but that the government would send a delegation to Doha for another round of talks.
Israeli public broadcaster Kan reported Monday that "the cabinet approved the departure of the delegation with a mandate to hold the negotiations. The delegation will leave today."
A source close to the talks said on condition of anonymity that a meeting between Barnea, Qatari Prime Minister Mohammed bin Abdulrahman Al-Thani and Egyptian officials "is expected to take place today."