Israel responded cautiously to President Trump’s declaration Thursday that the U.S.-Saudi nuclear deal would be contingent on Saudi Arabia joining the Abraham Accords.

Israeli officials warmly welcomed the possibility of establishing diplomatic ties with Saudi Arabia, but analysts suggested that Mr. Trump’s demand may offer a substance-free distraction from a deal that remained unmistakably bad for Israel.

The president’s statement on social media instantly led the news agenda in Israel, where the signing of the U.S.-Saudi agreement had been met with alarm on Wednesday, raising concerns of a Middle East arms race and fears that the country’s most powerful ally was forging its own path in the region, independent of Israel.

On Thursday, Prime Minister Benjamin Netanyahu continued to remain silent on the deal itself. But he seized on Mr. Trump’s demand for normalization of Saudi-Israeli ties to assert that the U.S.-Israeli war against Iran had “created the possibility to expand the circle of peace.”

“As President Trump has said, Saudi Arabia’s joining of the Abraham Accords would be an historic leap forward for peace in the Middle East,” Mr. Netanyahu said in a statement. “Peace through Strength.”

But national-security analysts cast doubts on the value of Mr. Trump’s promises, given that Saudi Arabia’s leaders have conditioned normalizing ties with Israel on solid progress toward a Palestinian state, which Mr. Netanyahu adamantly opposes.

“We shouldn’t look at what Trump just said; we should look at what’s in the agreement,” said Yoel Guzansky, an expert on Saudi Arabia and nuclear proliferation at the Institute for National Security Studies in Tel Aviv. The text of the deal had not been made public. “I think he meant well by this. But he’s not always connected to reality.”

Mr. Guzansky said he opposed the U.S.-Saudi deal because of the risk of nuclear proliferation, should the Saudis ever break with the United States and should the deal inspire Saudi rivals like Turkey or Egypt to pursue their own nuclear weapons.

He also flipped on its head Mr. Netanyahu’s argument that the U.S.-Israeli war with Iran had succeeded in creating an opportunity for peace, suggesting rather that the war had failed to meet its objectives and had added to the Saudis’ leverage.

Had the war gone differently, Mr. Guzansky said, “and in February we had toppled the regime and gotten the nuclear material out, would Trump have been able to give the Saudis enrichment, after there’s no more nuclear program in Iran? It would have been very hard for the Saudis to ask.”

Enrichment has been at the center of Israeli criticism of the deal. Officials familiar with its terms have described the agreement as allowing for a two-year study period during which Saudi and American officials will determine if there is a viable economic path for the kingdom to enrich nuclear fuel.

Mr. Trump muddied the waters on Thursday, saying in his post “there will be no enrichment of nuclear material.”

But some analysts noted that such a delay would offer at least a chance for Mr. Trump’s promise of Israeli-Saudi normalization to be fulfilled.

“Truthfully, Trump is articulating something that is implicitly embedded within the agreement that was signed,” said Tamir Hayman, a former head of Israeli military intelligence. The two-year period, he said, “allows Trump to pressure Saudi Arabia to reach normalization.”

“This is smart because during this period Trump is still in the White House,” Mr. Hayman added, “and there could be a change in Israel that would allow the Saudi ruler to move toward normalization, which is not relevant today.”

Such a change in Israel could occur as soon as October, when Mr. Netanyahu and his government are facing an election.