Israeli restrictions on the entry of humanitarian aid into Gaza may amount to the war crime of deliberate starvation, the UN has said, as the White House called for unimpeded access for aid to the coastal strip. Amid mounting and catastrophic hunger in parts of Gaza, and official UN figures for hunger levels which are the worst seen under the current classification system, the Biden administration added it was “deeply concerned” following a report about potential famine. The UN high commissioner for human rights, Volker Turk, said Israeli restrictions on the entry of aid may amount to “starvation as a method of war”. His comments follow the UN secretary general on Monday describing the food shortages as “entirely man-made” and an Integrated Food Security Phase Classification (IPC) report, the international standard for measuring food crises, warning of imminent famine in the territory’s north. “The extent of Israel’s continued restrictions on entry of aid into Gaza, together with the manner in which it continues to conduct hostilities, may amount to the use of starvation as a method of war, which is a war crime,” Turk said. While aid agencies blame Israel for blockading Gaza, the Israeli prime minister Benjamin Netanyahu’s government says it is facilitating aid and the UN and relief groups are at fault for any issues over the quantity and pace of delivery. “Israel, as the occupying power, has the obligation to ensure the provision of food and medical care to the population commensurate with their needs and to facilitate the work of humanitarian organisations to deliver that assistance,” Turk said via spokesperson Jeremy Laurence, describing the crisis as “human-made” and preventable. “Everyone, especially those with influence, must insist that Israel acts to facilitate the unimpeded entry and distribution of needed humanitarian assistance and commercial goods to end starvation and avert all risk of famine.” The issue of the flow of aid into Gaza has become a key point of friction between the Biden administration and Netanyahu, seeing the US and other countries both airdrop aid into Gaza and work to open a sea route from Cyprus. Officials and experts say, however, that land routes into Gaza, controlled by Israel, remain the most effective way of delivering aid to Palestinians who have been trapped by months of devastating conflict. Echoing the UN, Oxfam America and Human Rights Watch sent a memorandum detailing alleged Israeli breaches of international humanitarian law – including the obstruction of aid – to the Biden administration, calling for the suspension of US arms supplies to Israel. Written in reply to the Biden administration’s new National Security policy document (NSM-20) requiring recipients of US weapons to act in compliance with international law, the two groups said said Israel’s “assurances” of acting under international law “are not credible”. Accusing Israel of “systematically prevent[ing] aid” from reaching “the roughly 300,000 Palestinians who remain in northern Gaza, where the threat of starvation is most acute”. The memorandum added that in the first six weeks of this year, “over half of the planned humanitarian aid missions to northern Gaza were obstructed by Israeli authorities”. Charging Israel with a deliberate policy of starvation, the documents adds: “International humanitarian law prohibits parties to a conflict from deliberately causing ‘the population to suffer hunger, particularly by depriving it of its sources of food or of supplies’.” The UN secretary general, António Guterres, called for an immediate humanitarian ceasefire to allow the entry of aid into Gaza. “Palestinians in Gaza are enduring horrifying levels of hunger and suffering,” Guterres said in New York on Monday, describing the IPC report as an “appalling indictment of conditions on the ground for civilians”. Highly technical and often cautious, IPC classification reports are regarded as the international standard for measuring food security crises. The latest IPC report also represents hard evidence of the impact of Israeli policies on the flow of aid into Gaza. “This is the highest number of people facing catastrophic hunger ever recorded by the Integrated Food Security Classification system – anywhere, anytime,” Guterres added. “This is an entirely man-made disaster, and the report makes clear that it can be halted,” he warned, saying this showed the need for an immediate humanitarian ceasefire. “I call on the Israeli authorities to ensure complete and unfettered access for humanitarian goods throughout Gaza and for the international community to fully support our humanitarian efforts.” Israel on Monday asked the international court of justice not to issue emergency orders for it to step up humanitarian aid to Gaza to address a looming famine, dismissing South Africa’s request to do so as “morally repugnant”. In recent days warnings from global officials over the risk of famine in Gaza have escalated, with the head of USAid, Samantha Power, the latest to voice her concern. She said famine is imminent in Gaza, describing the IPC report as “horrific milestone” after just two previous famine declarations in the 21st century. “We call on Israel to take immediate action to put an end to this mass – and preventable – suffering,” she said. “Israel must do more to protect civilians and allow humanitarians to safely and consistently deliver assistance,” Power continued, calling for continued and sustained international efforts. She further called for increased safety and access for humanitarian agencies and international donors to scale lifesaving activities. “We continue to call on Israel to open more land routes into Gaza and reduce bottlenecks and inspection delays to get land crossings operating at full capacity, even as we pursue air and maritime operations to supplement those land routes,” Power added.