Thousands of Palestinian children in Gaza have been diagnosed with malnutrition, the World Health Organization (WHO) has said, as Israel continues to severely restrict supplies of food, water, medicine and fuel to the territory.

“A significant proportion of Gaza’s population is now facing catastrophic hunger and famine-like conditions,” WHO chief Tedros Adhanom Ghebreyesus told reporters on Wednesday.

“Despite reports of increased delivery of food, there is currently no evidence that those who need it most are receiving sufficient quantity and quality of food.”

Tedros said 8,000 children under five years old have been diagnosed and treated for acute malnutrition in Gaza.

“However, due to insecurity and lack of access, only two stabilisation centres for severely malnourished patients can operate,” the WHO chief added.

Tedros said 32 deaths in the besieged Palestinian enclave have been attributed to malnutrition.

United Nations officials have warned of the risk of famine as Israel continues its war on Gaza. In January, the International Court of Justice ordered Israel to “ensure the delivery of basic services and essential humanitarian aid to civilians in Gaza”.

The UN’s top court reasserted that ruling in March, demanding that Israel take “all necessary and effective measures to ensure, without delay… the unhindered provision at scale by all concerned of urgently needed basic services and humanitarian assistance”.

Some of Israel’s closest allies, including the United States, have also called for more aid to enter Gaza and reach people in need.

Last month, Israel seized and shut down the Palestinian side of the Rafah crossing between Gaza and Egypt, which had served as a major gateway for aid and humanitarian workers.

Last month, International Criminal Court prosecutor Karim Khan requested arrest warrants for Israeli Prime Minister Benjamin Netanyahu and Defence Minister Yoav Gallant on charges of alleged war crimes, including using “starvation of civilians as a method of warfare”.

A UN-backed independent commission also accused Israel of inflicting hunger on Palestinians.

“In relation to Israeli military operations and attacks in Gaza, the Commission found that Israeli authorities are responsible for the war crimes of starvation as a method of warfare, murder or wilful killing, intentionally directing attacks against civilians and civilian objects, forcible transfer, sexual violence, torture and inhuman or cruel treatment, arbitrary detention and outrages upon personal dignity,” the panel said in a report on Wednesday.

US Secretary of State Antony Blinken said earlier this week that Israel has taken “important steps” in recent months to remove obstacles to aid delivery in Gaza, but he acknowledged that it “can and must do more”.

“It is crucial to speed up the inspection of trucks and reduce backlogs; to provide greater clarity on – and shorten the list of – prohibited goods; to increase visas for aid workers and to process them more quickly,” he said at a Gaza aid conference in Jordan on Tuesday.

Blinken, who announced $404m in new assistance to Palestinians, also called for “clearer, more effective channels” to protect humanitarian workers from military operations.

Israeli attacks have killed at least 270 aid workers in Gaza, including seven World Central Kitchen employees in April – an incident that sparked global outrage.

Aid organisations have been stressing that even the inadequate aid that gets into Gaza often fails to reach people who need it most because of the Israeli offensive.

“The US’s latest humanitarian package for Gaza is a welcome step,” the International Rescue Committee said on Wednesday. “However, the effective delivery of any financial package depends wholly on unfettered access for aid and the ability for aid workers to operate seamlessly.”

Beyond Gaza, the WHO’s Tedros highlighted a growing health crisis in the occupied West Bank, where Israeli forces have killed hundreds of people since the outbreak of the war.

“WHO has documented 480 attacks on healthcare in the West Bank since the seventh of October last year, resulting in 16 deaths and 95 injuries,” he said.

In one major incident, undercover Israeli forces raided a hospital in Jenin and killed three people inside the medical centre.