Live updates: Follow the latest news on Israel-Gaza
Jordan and Egypt have intensified their opposition to what they regard as a possible expulsion of Palestinians, with officials warning any movement of refugees across their borders would constitute a regional threat.
Egypt rejects "eviction or attempts to liquidate the Palestinian question at the expense of neighbouring nations", read an official statement after President Abdel Fattah El Sisi chaired a meeting on Sunday of the country's National Security Council to discuss the war in Gaza.
It said there "will be no leniency in protecting" Egypt's security as the war entered its second week. Thousands of people on both sides, mostly non-combatants, have been killed.
The meeting occurred as Jordan's King Abdullah embarked on a European tour to alert the leaders of Britain, Italy, Germany and France of the impact of the war on Jordan.
The king told British Prime Minister Rishi Sunak in London "any attempt to expel the Palestinians" could result in "catastrophic consequences on the countries of the region".
"The king expressed Jordan's rejection to move the crisis to neighbouring countries and compounding the refugee issue," official television reported.
Jordan and Egypt were the first Arab nations to sign formal peace treaties with Israel. They are all US allies and the top three recipients of American aid.
Egypt and Jordan separately share borders with Gaza and Israeli-occupied territories in the West Bank, respectively.
Aside from the raging war between Hamas and Israel in Gaza, ongoing for nine days, there has been a surge in violence in the West Bank that could yet worsen.
Jordanian Prof Hasan Al Momani said Egypt and Jordan were co-ordinating closely to contain any repercussions of the war.
They have been among "the most engaged" on the Palestinian issue, partly because of repeated threats by the Israeli right to transfer the Palestinians in Gaza and the West Bank to the two countries.
"The co-ordination between Jordan and Egypt is very close on the Palestinian issue, particularly on this [expulsion possibility] side," said Mr Al Momani, who heads the international relations and regional studies department at the University of Jordan.
He said the public positions of the king and Mr El Sisi in the past several days have helped the US to formulate a position that rejects expulsion as a consequence of the current war, not far from the stance taken by the two men.
For decades, Egypt has criticised Israeli pressure on the Palestinians, fearing it could drive Gaza's 2.3 million residents into the sparsely populated Sinai Peninsula.
A similar "alternative homeland" scenario has long been feared by Jordanian authorities. Under such a scenario, a mass expulsion of West Bank Palestinians could drive another wave of refugees to Jordan, adding to the kingdom's large proportion of citizens and residents of Palestinian origin.
This could add strain to the balance between tribes who played a main role in creating Jordan as a British protectorate in 1921, and the later incomers from Palestine.
US Secretary of State Antony Blinken said the Biden administration "does not support proposals to relocate the Palestinians outside of Gaza“.
He said after meeting Mr El Sisi in Cairo that the idea was a "non-starter, so we do not support it".
In 1979, Egypt signed a peace treaty with Israel, followed 15 years later by Jordan.
Egypt’s House Speaker Hanafy El Gibaly urged the Palestinians to remain in Gaza, days after the Grand Imam of Al Azhar, one of highest seats of Islamic learning, issued a similar plea from Cairo.
