Explained | Why Palestinian displacement in Gaza war alarms the UN and Arabs

Beirut/Jerusalem: Israel's plans to storm a city sheltering more than half of Gaza's population are raising international concerns that a humanitarian crisis there could worsen sharply and drive Palestinians over the border to Egypt.

Israeli air strikes have in recent days started hitting Rafah, which lies right on the Egyptian border and is where hundreds of thousands of people displaced by violence further north are trapped in desperate conditions. Israeli forces are gearing up for a ground assault on the southern city.

For displaced Gazans, reports that Egypt is bracing for the possibility of a Palestinian exodus have only hardened their fears of being driven off the land entirely.

Three security sources said Egypt had begun preparing a desert area with some basic facilities which could be used to shelter Palestinians, emphasising this was a contingency step.

Egypt denied making any such preparations.

Palestinians have long been haunted by what they call the "Nakba", or catastrophe, when 700,000 of them were dispossessed from their homes when Israel was created in 1948.

Many were driven out or fled to neighbouring Arab states, including to Jordan, Syria and Lebanon, where many of them or their descendants still live in refugee camps. Some went to Gaza. Israel disputes the account that they were forced out.

The conflict since Oct. 7 has seen an unprecedented Israeli bombardment and land offensive in Gaza, devastating urban areas throughout the enclave. Palestinians and U.N. officials say there are no longer any safe areas inside Gaza to seek shelter.

UNRWA, a U.N. agency which provides Palestinians with aid and essential services, says there are nearly 1.5 million people in Rafah, six times the population compared to before Oct. 7.

Before Israel launched its ground offensive in Gaza, it initially told Palestinians in north Gaza to move to what it said were safe areas in the south. As the offensive expanded, Israel told them to head further south towards Rafah.

According to U.N. estimates, up to 85% of the 2.3 million people in Gaza - one of the most densely populated areas of the world - have already been displaced from their homes and are now crammed in an ever smaller area near the border.

There has been no precedent for people fleeing en masse from Gaza during conflicts and flare-ups with Israel in recent years, although no previous war has been this fierce. However, there have been incidents when Gaza's border with Egypt was breached, although those crossing numbered hundreds or thousands, and those people were not seeking shelter or to stay.

Following Israel's withdrawal from the Gaza Strip in 2005, Palestinians breached the fence, with some clambering over with make-shift ramps and using ropes. At one place, Palestinian militants rammed a concrete barrier to break a hole.

Hamas breached the frontier again in 2008, challenging a blockade imposed by Israel and Egypt after the group seized control of the Gaza Strip in 2007 from the West Bank-based Palestinian Authority. The border remained breached for about 10 days before Egypt resealed it.

Many Palestinians inside Gaza have said they would not leave even if they could because they fear it might lead to another permanent displacement in a repeat of 1948. Egypt, meanwhile, has kept the border firmly closed except to let a few thousand foreigners, dual nationals and a handful of others leave Gaza.

Egypt and other Arab nations strongly oppose any attempt to push Palestinians over the border.

Yet, the scale of this conflict eclipses other Gaza crises or flare-ups in past decades, and the humanitarian disaster deepens for Palestinians by the day.

From the earliest days of the conflict, Arab governments, particularly Israel's neighbours Egypt and Jordan, have said Palestinians must not be driven from land where they want to make a future state, which would include the West Bank and Gaza.

Like Palestinians, they fear any mass movement across the border would further undermine prospects for a "two-state solution" - the idea of creating a state of Palestine next to Israel - and leave Arab nations dealing with the consequences.

Top UN officials have added their voices to concerns about a mass displacement.

US President Joe Biden has said Israel should not proceed with a Rafah operation without a plan to ensure the safety of people sheltering there. Other allies of Israel have expressed concern about the prospect of a Rafah offensive.

UN aid chief Martin Griffiths said on Feb. 15 it was an "illusion" to think people in Gaza could evacuate to a safe place and warned of the possibility of Palestinians spilling into Egypt if Israel launches its operation in Rafah.

Israeli Prime Minister Benjamin Netanyahu has described Rafah as the "last bastion" of Hamas, with four battalions of gunmen, and that Israel cannot achieve its goal of eliminating the group while they remain there.

Israel has said its army is drawing up a plan to evacuate civilians from Rafah to other parts of the Gaza Strip.

Israeli Foreign Minister Israel Katz said on Feb. 16 Israel had no plans to deport Palestinians from Gaza. Israel would coordinate with Egypt on Palestinian refugees and find a way to not harm Egypt's interests, Katz added.

However, comments by some in the government have stoked Palestinian and Arab fears of a new Nakba.

Finance Minister Bezalel Smotrich called on Dec. 31 for Palestinian residents of Gaza to leave the besieged enclave. National Security Minister Itamar Ben-Gvir said the war presented an "opportunity to concentrate on encouraging the migration of the residents of Gaza."

After Jordanian Foreign Minister Ayman Safadi said on Dec. 10 that Israel's offensive was "a systematic effort to empty Gaza of its people," Israeli government spokesperson Eylon Levy called those comments "outrageous and false accusations."

If large numbers of Gazans are forced to flee Rafah and cross the border due to an Israeli offensive, that could constitute a violation of international humanitarian law, said André Nollkaemper, a professor of international law at the University of Amsterdam.

If Gazans fleeing across the border acted because they felt they had no option due to the threat of a massive military campaign, then "it seems that it would be highly, highly difficult to justify under international humanitarian law," he said.

Israel says it must eliminate Hamas and that its military operations are justified as self-defence. It has said it does all it can to protect the civilian population, avoid unnecessary death and operate within international law at all times.