According to Palestinian, Arab and European officials who have heard Mr. Abbas’s version of the conversation, Crown Prince Mohammed bin Salman presented a plan that would be more tilted toward the Israelis than any ever embraced by the American government, one that presumably no Palestinian leader could ever accept.

The Palestinians would get a state of their own but only noncontiguous parts of the West Bank and only limited sovereignty over their own territory. The vast majority of Israeli settlements in the West Bank, which most of the world considers illegal, would remain. The Palestinians would not be given East Jerusalem as their capital and there would be no right of return for Palestinian refugees and their descendants…

Even if the account proves incomplete, it has gained currency with enough players in the Middle East to deeply alarm Palestinians and raise suspicions about Mr. Trump’s efforts. On top of that, advisers have said the president plans to give a speech on Wednesday in which he would recognize Jerusalem as the capital of Israel, even though both sides claim it, a declaration that analysts and regional officials say could undermine America’s role as a theoretically neutral broker.