Israel's defence minister ordered the army on Thursday to prepare for "voluntary" departures from Gaza, as US President Donald Trump ruled out sending troops to the territory.
Trump had earlier proposed moving Palestinians out of Gaza, sparking uproar from leaders in the Middle East and beyond.
Hours later, Israeli Defence Minister Israel Katz said he had instructed the military to formulate a plan for Palestinians to leave Gaza, which has been ravaged by more than a year of war.
"I have instructed the IDF (military) to prepare a plan to enable voluntary departure for Gaza residents," Katz said, adding they could go "to any country willing to accept them".
Trump announced his proposal to audible gasps on Tuesday at a joint press conference with Israeli Prime Minister Benjamin Netanyahu, the first foreign leader to meet him at the White House since his inauguration.
The United Nations warned any forced displacement of Palestinians would be "tantamount to ethnic cleansing".
Trump insisted "everybody loves" the plan, saying it would involve the United States taking over Gaza, though he offered few details on how more than two million Palestinians would be removed.
His administration later appeared to backtrack, with Secretary of State Marco Rubio saying any transfer of Gazans would be temporary.
Trump doubled down on his proposal on Thursday, however.
"The Gaza Strip would be turned over to the United States by Israel at the conclusion of fighting," he said on his Truth Social network.
"No soldiers by the US would be needed! Stability for the region would reign!!!"
Hamas's spokesman condemned Trump's statements as "absolutely unacceptable".
"Trump's remarks about Washington taking control of Gaza amount to an open declaration of intent to occupy the territory," Hazem Qassem said.
"Gaza is for its people and they will not leave.
Netanyahu, speaking to Fox News on Wednesday, called the proposal "remarkable" and hailed Trump as Israel's "greatest friend."
"I think it should be really pursued, examined, pursued and done, because I think it will create a different future for everyone."
Katz said Trump's plan "could create broad opportunities for Gaza residents who wish to leave, help them integrate optimally in host countries, and also facilitate the advancement of reconstruction programs for a demilitarised, threat-free Gaza."
Far-right Israeli Finance Minister Bezalel Smotrich — who has repeatedly expressed support for Trump's proposal to relocate Gazans, and who vowed Wednesday to "definitively bury" the idea of a Palestinian state -- said he welcomed Katz's move.
Palestinians residing in the coastal territory have vowed not to leave. For them, any attempt to push them out of Gaza recalls the "Nakba", or "catastrophe" — the mass displacement of Palestinians during Israel's creation in 1948.
"They can do whatever they want, but we will remain steadfast in our homeland," said 41-year-old Gazan Ahmed Halasa.
Israelis in Jerusalem largely welcomed Trump's proposal, though some doubted it could be carried out.
"I really like what he said, but in my wildest dreams... it's hard for me to believe it will happen, but who knows," said 65-year-old Refael.
White House Press Secretary Karoline Leavitt said Trump wanted Palestinians to only be "temporarily relocated" out of Gaza.
"It's not a liveable place for any human being," she said.
But Trump, who also suggested he might visit Gaza, implied it would not be rebuilt for Palestinians.
Even before Tuesday's announcements, Trump had suggested residents of Gaza should move to Egypt and Jordan, both of which have flatly rejected any resettlement of Palestinians on their territory.
Egypt's foreign ministry on Thursday said Israeli support for Trump's plan "weakens and destroys the negotiations on a ceasefire agreement and incites a return to fighting".
Egypt, Qatar and the United States mediated the fragile January 19 ceasefire between Israel and Hamas. Talks resumed this week for the second phase of the truce, expected to herald a more permanent end to the fighting.
UN Secretary-General Antonio Guterres emphasised "the inalienable rights of the Palestinian people... to simply live as human beings in their own land".
His spokesman Stephane Dujarric said: "Any forced displacement of people is tantamount to ethnic cleansing."
Israel's military offensive in response to Hamas's attack has left much of Gaza in ruins, including schools, hospitals and most civil infrastructure.
Human Rights Watch said the destruction of Gaza "reflects a calculated Israeli policy to make parts of the strip unliveable".
Trump's plan "would move the US from being complicit in war crimes to direct perpetration of atrocities", said HRW regional director Lama Fakih.
In a bid to address the dire humanitarian situation, aid has been rushed into the territory since the ceasefire took effect.
UN humanitarian chief Tom Fletcher said Thursday that more than 10,000 aid trucks had crossed into Gaza since the truce went into effect, calling it "a massive surge".
Agence France-Presse