All United Nations Security Council members, except the United States, on Wednesday said the famine in Gazawas a “manmade crisis” and warned that the use of starvation as a weapon of war is banned under international humanitarian law.

In a joint statement, the 14 council members called for an immediate, unconditional and permanent ceasefire, the release of all hostages held by Hamas and other groups, a substantive surge of aid throughout Gaza, and for Israel to immediately and unconditionally lift all restrictions on aid delivery.

"Famine in Gaza must be stopped immediately," they said. "Time is of the essence. The humanitarian emergency must be addressed without delay and Israel must reverse course."

Gaza City and surrounding areas are officially suffering from famine, and it will likely spread, a global hunger monitor determined on Friday. The Integrated Food Security Phase Classification system said 514,000 people - nearly a quarter of Palestinians in Gaza - are experiencing famine and that is due to rise to 641,000 by the end of September.

Israel asked a global hunger monitor on Wednesday to retract an assessment. Israel dismissed the findings as false and biased, saying the IPC had based its survey on partial data largely provided by Hamas, which did not take into account a recent influx of food.

At a UN Security Council meeting on Gaza on Wednesday, acting US Ambassador to the UN Dorothy Shea questioned the credibility and integrity of the IPC report, saying it "doesn’t pass the test on either."

"We all recognize that hunger is a real issue in Gaza and that there are significant humanitarian needs which must be met. Addressing those needs is a priority for the United States," she told the 15-member council.