The International Court of Justice (ICJ) has unanimously ordered Israel, accused by South Africa of genocide in Gaza, to take all necessary and effective action to ensure basic food supplies to the territory's Palestinian population and stop spreading famine.
However, Hamas - the rulers of Gaza - said a ceasefire was needed to halt the humanitarian crisis.
The order came as Israeli forces and militants battled in close combat around Al Shifa Hospital in Gaza City, where the armed wings of Hamas and Islamic Jihad said they attacked Israeli soldiers and tanks with rockets and mortar fire.
Judges at the ICJ, also known as the World Court, said that Palestinians in Gaza face worsening conditions and famine and starvation were spreading.
"The court observes that Palestinians in Gaza are no longer facing only a risk of famine ... but that famine is setting in," the judges said in their order.
The new measures were requested by South Africa as part of its ongoing case that accuses Israel of state-led genocide in Gaza.
Senior Hamas official Basem Naim said the ruling did not go far enough and Israel must be ordered to end its military offensive to halt the suffering.
"We welcome any new demands to end this humanitarian tragedy in Gaza and especially in the northern Gaza Strip, but we hoped the court ordered a ceasefire as an absolute solution to all the miseries our people in Gaza are living through," he said.
The United Nations Security Council voted on Tuesday to demand an immediate ceasefire and the unconditional release of all hostages. The United States abstained from, but did not veto, the vote.
There was no immediate comment from Israel's Foreign Ministry on the court ruling.
Higgins urges action to deliver aid, free hostages
President Michael D Higgins said the ICJ order "cannot be ignored" and that all countries must "do all they can" to secure the delivery of aid to Gaza as well as a ceasefire and the release of hostages.
In a statement, he said: "Today's new order by the International Court of Justice that Israel ensure the unhindered provision at scale of urgently needed basic services and humanitarian assistance - including food, water and medicine - and open more land crossings in order to prevent the spread of famine and starvation cannot be ignored.
"It is now not morally acceptable that a single voice would be silent in the European Union or international community, all countries must do all that they can to ensure the immediate delivery of aid, a ceasefire and the release of all hostages in line with this week's UN Security Council resolution."
Israel has said it is making efforts to expand access for humanitarian groups to Gaza overland, through air drops and by ship to the enclave's Mediterranean coast.
The Israeli army said it continued to operate around the Al Shifa Hospital complex after storming it more than a week ago.
Its forces have killed around 200 gunmen since the start of the operation "while preventing harm to civilians, patients, medical teams, and medical equipment", the army said.
Gaza's health ministry said that patients were being held inside an administration building in Al Shifa that was not equipped to provide them with healthcare.
Five people had died since the Israeli raid began due to shortages of food, water and medical care, the Hamas-run ministry said.
Director of the Gaza Hamas-run government media office Ismail Al-Thawabta said the Israeli army is carrying out "field killings and executions against hundreds of civilians".
"We doubt the occupation's narrative because it consistently lies and deceives against our people.
"Everyone inside the Shifa complex are civilians, and there are no military personnel inside the compound," he said in response to the Israeli army statement.
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Al Shifa - Gaza's biggest hospital before the war - had been one of the few healthcare facilities even partially operational in the north of the territory before the latest fighting.
It had also been housing displaced civilians.
Unverified footage on social media showed its surgery unit blackened by flames and nearby apartments on fire or destroyed.
The armed wings of the Hamas and Islamic Jihad militant groups said in a statement they "bombed, with a barrage of mortar shells, gatherings of Israeli soldiers in the vicinity of the Al-Shifa Complex" in a joint operation.
Islamic Jihad targeted an Israeli tank with an anti-tank rocket outside the hospital, it said in another statement.
The Israeli military said militants fired at its troops from inside and outside the emergency department building.
Israel said it is targeting Hamas militants who use civilian buildings, including apartment blocks and hospitals, for cover, but the group denies doing so.
At least 32,552 Palestinians have been killed and 74,980 wounded in Israel's military offensive since 7 October, Gaza's health ministry said.
Thousands more dead are believed to be buried under rubble and more than 80% of Gaza's 2.3 million population is displaced, many at risk of famine.
The war erupted after Hamas militants broke through the border and rampaged through communities in southern Israel, killing 1,200 people and abducting 253 hostages, according to Israeli tallies.
Israeli forces continued to blockade Al-Amal and Nasser hospitals in Khan Younis, in southern Gaza, while several other areas came under Israeli fire, residents said.
The Palestinian Red Crescent said seven people working for the organisation arrested in a raid on Al-Amal Hospital on 9 February had been released after 47 days in Israeli prisons.
Among them was the director of ambulance and emergency services in Gaza, Mohammed Abu Musabeh.
Eight members of the association were still being detained, it said in a statement.
Israel said soldiers from its Commando Brigade had arrested dozens of Palestinian militants in the Al-Amal area and discovered explosives and dozens of Kalashnikov-type weapons.
The World Health Organization said Al-Amal Hospital had ceased to function due to fighting, leaving just ten of 36 hospitals in Gaza partially operational.
"Once more, WHO demands an immediate end to attacks on hospitals in Gaza, and calls for protection of health staff, patients, and civilians," its Director-General Tedros Adhanom Ghebreyesus wrote on social media.
In Rafah, where more than one million people have been sheltering, health officials said an Israeli airstrike on a house killed eight people and wounded others.
Israel said it plans a ground offensive into Rafah, where it believes most Hamas fighters are sheltering.
The United States - its closest ally and main arms supplier - opposes such an assault, arguing it would cause too much harm to civilians who have sought refuge there.
