The Palestinian president has said he strongly rejects President Donald Trump's proposal for the US to take over Gaza and permanently resettle the 2.1 million Palestinians living there.
"We will not allow the rights of our people... to be infringed on," Mahmoud Abbas stressed, warning that Gaza was "an integral part of the State of Palestine" and forced displacement would be a serious violation of international law.
Hamas, whose 15-month war with Israel has caused widespread devastation, said Trump's plan would "put oil on the fire" in the region.
Arab states also rejected the idea, with Saudi Arabia reiterating it would not normalise ties with Israel without the establishment of a Palestinian state.
Neighbouring Egypt, who had rejected Trump's suggestion last month that it and Jordan take in residents of Gaza, stressed the need for reconstruction "without moving the Palestinians".
It comes two weeks after the start of a fragile ceasefire in Gaza, during which Hamas has released some Israeli hostages it is holding in exchange for Palestinian prisoners in Israeli jails.
The Israeli military launched a campaign to destroy Hamas in response to an unprecedented cross-border attack on 7 October 2023, in which about 1,200 people were killed and 251 were taken hostage.
More than 47,540 people have been killed and 111,600 injured in Gaza since then, according to the territory's Hamas-run health ministry.
Most of Gaza's population has also been displaced multiple times, almost 70% of buildings are estimated to be damaged or destroyed, the healthcare, water, sanitation and hygiene systems have collapsed, and there are shortages of food, fuel, medicine and shelter.
President Trump's first major remarks on Middle East policy shattered decades of US thinking on the Israeli-Palestinian conflict.
He presented them at the White House on Tuesday night alongside visiting Israeli Prime Minister Benjamin Netanyahu.
"The US will take over the Gaza Strip, and we will do a job with it too," he said. "We'll own it and be responsible for dismantling all of the dangerous unexploded bombs and other weapons on the site, level the site, and get rid of the destroyed buildings."
Trump estimated that about 1.8 million Palestinians living in Gaza would have to be relocated to achieve his vision of creating "the Riviera of the Middle East", and said they would be housed in Jordan, Egypt and other countries.
When asked whether the refugees would eventually be allowed to return, he said that "the world's people" would live in Gaza, before adding "also Palestinians".
Trump also brushed aside previous objections from Jordan and Egypt's leaders to taking in refugees, insisting that they would eventually "open their hearts and will give us the kind of land that we need to get this done".
Netanyahu said Trump's proposal could "change history" and was "worth paying attention to", adding: "This is the kind of thinking that will reshape the Middle East and bring peace."
A unnamed senior Israeli official was also quoted as saying that Trump's ideas surpassed all his "expectations and dreams".
However, the Palestinian leadership condemned the plan in a statement issued on Wednesday.
"These calls represent a serious violation of international law," President Abbas said, adding that "peace and stability will not be achieved in the region without the establishment of a Palestinian state".
Abbas leads Hamas rivals Fatah and governs parts of the Israeli-occupied West Bank.
He declared that Palestinians would not "give up their land, rights, and sacred sites" and that "the Gaza Strip is an integral part of the land of the State of Palestine, along with the West Bank and East Jerusalem".
Hamas - which is proscribed as a terrorist organisation by Israel, the US, the UK and other countries - said in a statement that Trump was "aiming for the United States to occupy the Gaza Strip".
It warned that his proposal was "aggressive to our people and cause, won't serve stability in the region and will only put oil on the fire".
Palestinians in Gaza also said the plan was completely out of the question.
"We have endured nearly a year and a half of bombings and destruction, yet we remain in Gaza," one man told BBC Arabic.
"We would rather die in Gaza than leave it. We will stay here until we rebuild it. Trump can do as he pleases, but we firmly reject his decisions."
Under international law, attempts to forcibly transfer populations are strictly prohibited.
Palestinians also fear a repeat of the "Nakba", or "catastrophe", when hundreds of thousands fled or were driven from their homes during the war that followed the creation of the State of Israel in 1948.
Many of those refugees ended up in Gaza, where they and their descendants make up three quarters of the population. Another 900,000 registered refugees live in the West Bank, which Israel occupied in the 1967 Middle East war along with Gaza, while 3.4 million others live in Jordan, Syria and Lebanon, according to the UN.
Israel unilaterally withdrew its troops and settlers from Gaza in 2005, though it retained control of its shared border, airspace and shoreline, giving it effective control of the movement of people and goods. The UN still regards Gaza as Israeli-occupied territory because of the level of control Israel has.
Saudi Arabia's foreign ministry said the kingdom "unequivocally rejected" Trump's proposal for post-war Gaza and reiterated that it would continue its efforts to establish an independent Palestinian state and "not establish diplomatic relations with Israel without that".
"Achieving lasting and just peace is impossible without the Palestinian people obtaining their legitimate rights," it added.
Following talks in Cairo, Egyptian Foreign Minister Badr Abdelatty said he had agreed with Palestinian Authority Prime Minister Mohammed Mustafa on "the importance of moving forward with early recovery projects... without the Palestinians leaving the Gaza Strip, especially with their commitment to their land and refusal to leave it".
Turkish Foreign Minister Hakan Fidan said the relocation of Palestinians from Gaza in any form was "unacceptable", adding: "It is absurd to even consider it."
Western governments also expressed alarm about any forced displacement.
France's foreign ministry said it would "constitute a serious violation of international law, an attack on the legitimate aspirations of the Palestinians, but also a major obstacle to the two-state solution and a major destabilising factor for our close partners Egypt and Jordan, as well as for the entire region".
UK Foreign Secretary David Lammy said: "We've always been clear in our belief that we must seek two states. We must see Palestinians able to live and prosper in their homelands, in Gaza, in the West Bank."