(Reuters) - Extreme food shortages in parts of the Gaza Strip have already exceeded famine levels, and mass death is now imminent without an immediate ceasefire and surge of food to areas cut off by fighting, the global hunger monitor said on Monday.

The Integrated Food-Security Phase Classification (IPC), whose assessments are relied on by U.N. agencies, said 70% of people in parts of northern Gaza were suffering the most severe level of food shortage, more than triple the 20% threshold to be considered famine.

The IPC said it did not have enough data on death rates, but estimated residents would be dying at famine scale imminently, defined as two people out of every 10,000 dying daily from starvation or from malnutrition and disease.

Gaza's health ministry has said 27 children and three adults have died so far from malnutrition.

"The actions needed to prevent famine require an immediate political decision for a ceasefire together with a significant and immediate increase in humanitarian and commercial access to the entire population of Gaza," it said.

In all, 1.1 million Gazans, around half the population, were experiencing "catastrophic" shortages of food, with around 300,000 in the areas now facing the prospect of famine-scale death rates.

The prospect of a manmade famine in Gaza has brought the strongest criticism of Israel from Western allies since it launched its war against Hamas militants following their deadly attack on Israeli territory on Oct. 7.

"In Gaza we are no longer on the brink of famine. We are in a state of famine... Starvation is used as a weapon of war. Israel is provoking famine," EU foreign policy chief Josep Borrell said at a Brussels conference on aid for Gaza.

Israeli Foreign Minister Israel Katz responded that Borrell should "stop attacking Israel and recognise our right to self-defence against Hamas' crimes".

Israel allowed "extensive humanitarian aid into Gaza by land, air, and sea for anyone willing to help", Katz said on X, and aid was "violently disturbed" by Hamas militants with "collaboration" by the U.N.'s aid agency UNRWA.

U.N. Secretary-General Antonio Guterres called the IPC report an "appalling indictment" and said Israel must allow complete and unfettered access to all parts of Gaza.

Britain's foreign minister David Cameron said he would carefully review the report: "It's clear the status quo is unsustainable. We need urgent action now to avoid a famine."

Israel, which initially allowed aid into Gaza through only two checkpoints on the enclave's southern edge, says it is opening more routes by land, as well as allowing sea shipments and air drops. The first boat carrying aid arrived last week.

Aid agencies say they still cannot get enough supplies through or distribute them safely, especially in the north.