UNITED NATIONS: The United Nations on Tuesday warned that an Israeli assault on Rafah in the Gaza Strip was "on the immediate horizon" and that "incremental" progress by Israel on aid access to the enclave could not be used to prepare for or justify an operation.

U.N. Secretary-General Antonio Guterres appealed for states with influence over Israel "to do everything in their power" to prevent an Israeli assault on Rafah in southern Gaza, where more than 1.2 million displaced Gaza Palestinians are sheltering.

Israel's Prime Minister Benjamin Netanyahu vowed on Tuesday to go ahead with a long-promised assault, whatever the response by Hamas to latest proposals for a halt to fighting in the nearly seven-month-long war and a return of Israeli hostages.

"The world has been appealing to the Israeli authorities for weeks to spare Rafah, but a ground operation there is on the immediate horizon," said U.N. aid chief Martin Griffiths in a statement. "The simplest truth is that a ground operation in Rafah will be nothing short of a tragedy beyond words."

Israel pledged nearly a month ago to improve aid access to the enclave of 2.3 million people after U.S. President Joe Biden demanded steps to alleviate the humanitarian crisis, saying the U.S. could place conditions on support if Israel did not act.

Guterres told reporters that there had been "incremental progress" toward averting "an entirely preventable, human-made famine" in northern Gaza, but much more was urgently needed.

"These improvements in bringing more aid into Gaza cannot be used to prepare for or justify a full-blown military assault on Rafah," Griffiths said.

Guterres specifically called on Israel to follow through on its promise to open two crossings to the north.

"A major obstacle to distributing aid across Gaza is the lack of security for humanitarians and the people we serve. Humanitarian convoys, facilities and personnel, and the people in need must not be targets," Guterres told reporters.

NO ALTERNATIVE TO LAND

A U.N.-backed report in March said famine was imminent and likely by May in northern Gaza, and could spread across the enclave by July. Guterres said the most vulnerable in the north "are already dying of hunger and disease."

When asked what leverage the U.S. could use over its ally Israel to boost aid access and avert a Rafah assault, Guterres said: "It is very important to put all possible pressure in order to avoid what would be an absolutely devastating tragedy."

U.S. Secretary of State Antony Blinken has said he will discuss with Netanyahu on Wednesday measures that Israel still needs to take to increase the flow of aid into Gaza.

"I strongly encourage the government of Israel and the Hamas leadership to reach now an agreement," Guterres said. "Without that, I fear the war, with all its consequences both in Gaza and across the region, will worsen exponentially."

The U.N. is in talks with the U.S. about a floating pier it is constructing to allow maritime aid deliveries to Gaza from Cyprus. Guterres said: "We welcome aid delivery by air and sea, but there is no alternative to the massive use of land routes."

Israel's Deputy U.N. Ambassador Jonathan Miller said last week that Israel continued "to elevate and step up" its aid support and that there had been substantial results with a "dramatic increase" in the volume of aid over the past several months.

Israel is retaliating against Hamas in Gaza over an Oct. 7 surprise attack on southern Israel led by the  group.

Israel says about 1,200 people were killed and more than 250 people were taken hostage in the assault. Gaza health authorities say Israel has killed more than 34,000 people in its offensive in Hamas-run Gaza since then.