Israel ended its ceasefire with the Hamas militant group and renewed its air and ground war earlier in March.
At the beginning of March it cut off all supplies of food, fuel, medicine and humanitarian aid to the territory's roughly two million Palestinians to pressure Hamas to accept changes to the truce agreement.
The evacuation orders appeared to cover nearly all the city and nearby areas. The military ordered Palestinians to head to Muwasi, a sprawl of squalid tent camps along the coast.
The orders came during Eid al-Fitr, a normally festive Muslim holiday marking the end of the fasting month of Ramadan.
Israel launched a major operation in Rafah, on the border with Egypt, last May, leaving large parts of it in ruins.
The military seized a strategic corridor along the border as well as the Rafah crossing with Egypt, Gaza's only gateway to the outside world that was not controlled by Israel.
Israel was supposed to withdraw from the corridor under the ceasefire it signed with Hamas in January under US pressure, but it later refused to, citing the need to prevent weapons smuggling.
Israel has vowed to intensify its military operations until Hamas releases the remaining 59 hostages it holds — 24 of whom are believed to be alive.
Israel has also demanded that Hamas disarm and leave the territory, conditions that were not included in the ceasefire agreement and which Hamas has rejected.
Israeli Prime Minister Benjamin Netanyahu said on Sunday that Israel would take charge of security in Gaza after the war and implement US President Donald Trump's proposal to resettle Gaza's population in other countries, describing it as "voluntary emigration".
That plan has been universally rejected by Palestinians, who view it as forcible expulsion from their homeland, and human rights experts say it would likely violate international law.
Hamas, meanwhile, has insisted on implementing the signed agreement, which called for the remainder of the hostages to be released in exchange for a lasting ceasefire and an Israeli pullout.
Negotiations over those parts of the agreement were supposed to have begun in February but only preliminary talks have been held.
The war began when Hamas-led militants stormed into Israel on October 7, 2023, rampaging through army bases and farming communities and killing some 1200 people, mostly civilians.
The militants took another 251 people hostage, most of whom have since been released in ceasefires or other deals.
Israel's retaliatory offensive has killed more than 50,000 Palestinians, according to Gaza's Health Ministry, which does not say how many were civilians or combatants.
At its height, the war had displaced some 90 per cent of Gaza's population, with many fleeing multiple times.
Large areas of Gaza have been destroyed, and it's unclear how or when anything will be rebuilt.
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