Normalization is only possible with Biden’s leadership.

Saudi Arabia is seeking security guarantees from the United States, help with developing a civilian nuclear program and fewer restrictions on U.S. arms sales as its price for normalizing relations with Israel, people familiar with the exchanges say.

If sealed, the deal could set up a major political realignment of the Middle East.

Riyadh’s ambitious request offers President Biden the chance to broker a dramatic agreement that would reshape Israel’s relationship with the most powerful Arab state. It could also fulfill his pledge to build on the Trump-era Abraham Accords, which brokered similar diplomatic deals between Israel and other Arab nations, including the United Arab Emirates, Bahrain and Morocco.

A normalization deal would also fulfill one of the most cherished goals of Prime Minister Benjamin Netanyahu of Israel, capping what he considers a legacy of increasing Israel’s security against its archenemy, Iran. The deal would strengthen regional alliances, analysts say, while downgrading the relative importance of the Palestinian issue.

Officials and experts in the United States and the Middle East were divided on how seriously to take the proposal, given the frosty relations between Mr. Biden and Mohammed bin Salman, Saudi Arabia’s crown prince.

News of the Saudi proposal emerged hours before a separate agreement, brokered by China, which paved the way for Riyadh to restore diplomatic relations with Iran for the first time in seven years. Some analysts called the deal evidence that Saudi Arabia had lost trust in the United States as a defender of its security and is drawing nearer to China while seeking to ease its longtime rivalry with Iran as a hedging strategy. The development could possibly create new urgency in the Biden administration to broker an agreement between Saudi Arabia and Israel, but the immediate effects were unclear.

Still, there are numerous challenges standing in the way of a Saudi-Israeli deal. Violence between Israel and the Palestinians has been rising under the country’s new right-wing government in recent weeks. The Saudi government has issued repeated public condemnations of Israeli actions, dimming the near-term prospect of a deal. Analysts say a major escalation such as a new Palestinian intifada, or uprising, would render an agreement impossible.

Saudi officials have said they cannot forge normal relations with Israel — a step that would include formal diplomatic interactions and likely also trade and travel agreements — before a Palestinian state is established. But some people familiar with the discussions said they believe the Saudis, who have been building closer unofficial ties to Israel, would settle for less than that. The discussions were reported earlier by The Wall Street Journal.

“It’s interesting for a number of reasons,” said Martin Indyk, a former U.S. ambassador to Israel in the Clinton administration.

Mr. Netanyahu “wants it badly, and he can only get it with Biden’s help,” Mr. Indyk said. “That creates a situation where Biden has leverage over Netanyahu to persuade him that nothing good can happen with Saudi Arabia if he allows the situation in the West Bank and East Jerusalem to explode.”

He added that Mr. Biden would also see full normalization between the countries as being in the United States’ interest, particularly as a means of countering Iranian influence. Biden officials have long said it is their goal to build on the Trump-era accords.

But other obstacles remain. U.S. officials have long been wary of Saudi efforts to establish a civilian nuclear program. They fear it could be a first step toward a nuclear weapon, which Riyadh may seek as insurance against a potentially nuclear-armed Iran. It is unclear what the terms of a security agreement might be, but they are likely to be well short of a mutual defense guarantee like the one that binds NATO nations, people familiar with the discussions said.

Even if Mr. Biden were willing to meet Prince Mohammed’s terms, he would likely encounter firm resistance in Congress, where many Democrats have recently pressed to downgrade relations with the Saudi kingdom.

“Our relationship with Saudi Arabia has to be a direct bilateral relationship,” said Senator Christopher S. Murphy, Democrat of Connecticut and a member of the Foreign Relations Committee. “It should not run through Israel.”