A decadeslong history of violent conflict is among the reasons that countries in the region are opposed to providing a haven for the war-weary Gazans.

President Trump said he had spoken to Jordan’s leader and planned to call Egypt’s. Mr. Trump’s suggestion echoes proposals from far-right Israelis. A Hamas official rejected the idea.

Trump floated the idea on Saturday, saying he would urge the leaders of the two Arab countries to take in Gaza’s now largely homeless population, so that “we just clean out that whole thing.”