Israel said it had taken 100 people into custody at one of Gaza's main hospitals Saturday after troops raided the facility, with fears mounting for patients and staff trapped inside.
The deadly bombardment of Gaza continued overnight with another 100 people killed in Israeli strikes, according to the Hamas-run health ministry.
At least 120 patients and five medical teams are stuck without water, food and electricity in the Nasser hospital in Gaza's main southern city of Khan Yunis, according to the health ministry.
Israel has for weeks concentrated its military operations in Khan Yunis, the hometown of Hamas's Gaza leader Yahya Sinwar, the alleged architect of the October 7 attack that triggered the war.
Intense fighting has raged around the Nasser hospital -- one of the Palestinian territory's last major medical facilities that remains even partly operational.
The power was cut and the generators stopped after the raid, leading to the deaths of six patients due to a lack of oxygen, according to Gaza's health ministry.
"New-born children are at a risk of dying in the next few hours," the ministry warned Saturday.
Israel's army said troops entered the hospital on Thursday, acting on what it said was "credible intelligence" that hostages seized in the October 7 attack had been held there and that the bodies of some may still be inside.
It said it has detained 100 people from the hospital suspected of "terrorist activity", seized weapons and retrieved "medications with the names of Israeli hostages" in the hospital.
But the raid has been criticised by medics and the United Nations. The army has insisted it made every effort to keep the hospital supplied with power, including bringing in an alternative generator.
A witness, who declined to be named for safety reasons, told AFP the Israeli forces had shot "at anyone who moved inside the hospital".
- 'Pattern of attacks' -
World Health Organization spokesperson Tarik Jasarevic slammed the operation Friday, saying "more degradation to the hospital means more lives being lost".
"Patients, health workers, and civilians who are seeking refuge in hospitals deserve safety and not a burial in those places of healing," he said.
Doctors Without Borders said its medics had been forced to flee and leave patients behind, with one employee unaccounted for and another detained by Israeli forces.
The Gaza war began with Hamas' October 7 attack which resulted in the deaths of about 1,160 people in Israel, mostly civilians, according to an AFP tally based on official Israeli figures.
Militants also took about 250 people hostage, 130 of whom are still in Gaza, including 30 who are presumed dead, according to Israeli figures.
Israel's subsequent assault on Gaza has killed at least 28,858 people, mostly women and children, according to the territory's health ministry.
Israel has repeatedly accused Hamas of using hospitals for military purposes, which the Palestinian Islamist group has denied.
The UN Human Rights Office said the Nasser hospital raid appeared to be "part of a pattern of attacks by Israeli forces striking essential life-saving civilian infrastructure".
- 'Die from hunger' -
High-level negotiations to pause the war were held this week in Cairo, but their outcome is still unclear.
A day after US President Joe Biden called for a "temporary truce" to secure the release of hostages, Hamas chief Ismail Haniyeh on Saturday reiterated the group's demands, including a complete pause in fighting, the release of Hamas prisoners, and withdrawal of Israeli troops.
Qatar-based Haniyeh said Hamas would "not agree to anything less".
Biden has also urged Israeli Prime Minister Benjamin Netanyahu not to launch an offensive in Rafah without a plan to keep civilians safe -- but Netanyahu insisted he would push ahead with a "powerful" operation there to defeat Hamas.
Around 1.4 million displaced civilians are trapped in Rafah after taking refuge in a makeshift encampment by the Egyptian border, with dwindling supplies.
"We are dying slowly due to the scarcity of resources and the lack of medications and treatments," said displaced Palestinian Mohammad Yaghi.
In northern Gaza, many are so desperate for food they are grinding up animal feed.
"We need food now," said Mohammed Nassar, 50, from Jabalia in northern Gaza.
"We're going to die from hunger, not by bombs or missiles."
With the UN warning that Gazans are close to famine, the head of its agency for Palestinian refugees accused Israel of waging a campaign to "destroy" it entirely.
Israel has called for UNRWA chief Philippe Lazzarini to resign following claims a Hamas tunnel was discovered under its Gaza City headquarters.
Lazzarini told Swiss media Tamedia that the tunnel was 20 metres underground, and UNRWA didn't have the capabilities to search below ground in Gaza. More than 150 UNRWA installations have been hit during the war, he said.
- Regional tensions -
Hamas's armed wing has warned hostages in Gaza are also "struggling to stay alive" as conditions deteriorate due to relentless Israeli bombardments.
The Wall Street Journal reported this week that Egypt was building a walled camp near the border to accommodate Palestinians displaced from Gaza, citing Egyptian officials and security analysts.
Satellite images obtained by AFP show machinery building a wall along the highly secure frontier.
With the conflict now in its fifth month, regional tensions remain high.
Hamas ally Hezbollah and arch-foe Israel have been exchanging near-daily border fire since the start of the Israel-Hamas war.
The leader of the Iran-backed Hezbollah movement, Hassan Nasrallah, vowed that Israel would pay "with blood" for civilians it has killed in Lebanon.
By Mai Yaghi With Phil Hazlewood In Jerusalem