GAZA: One in three children below the age of two in northern Gaza is now "acutely malnourished", and famine is looming, the main UN agency operating in the Palestinian enclave said on Saturday as quoted by media reports.

"Children's malnutrition is spreading fast and reaching unprecedented levels in Gaza," the UN Relief and Works Agency for Palestine Refugees (UNRWA) said in a social media post.

More than five months into Israel's air and ground campaign in Gaza, triggered by Hamas's devastating attack on October 7, much of the enclave is in ruins with most of its 2.3 million population displaced and facing a major humanitarian crisis, The Times of Israel reported.

Western countries have called on Israel to do more to allow in aid, with the UN saying it faced "overwhelming obstacles," including crossing closures, onerous vetting, restrictions on movement and unrest inside Gaza.

Israel said it puts no limit on humanitarian aid for civilians in Gaza and blames slow aid delivery on incapacity or inefficiency among UN agencies, The Times of Israel reported.

Air and sea relief deliveries into Gaza have started, but aid agencies say these are no substitute for bringing in supplies by land.

Israel has accused UNRWA of complicity with Hamas, saying some staff members took part in the October 7 onslaught, and has called for the agency to be dismantled. Several major donors have paused funding over the allegations.