US Secretary of State Antony Blinken said Tuesday he was unsure whether Israel was ready to make compromises to reach a deal to normalize relations with Saudi Arabia, notably on a pathway to a Palestinian state.

His frank assessment came after Jake Sullivan, President Joe Biden's national security advisor, visited both countries and briefed Prime Minister Benjamin Netanyahu on the "potential" for a historic accord.

But Blinken, who has repeatedly shuttled between the two countries since the October 7 Hamas attack on Israel, acknowledged doubts about whether Netanyahu and his hard-right government would meet Saudi requests if the normalization issue became more than "hypothetical."

"I can't tell you whether Israel -- whether it's the prime minister or the country as a whole -- is prepared to do in this moment what would be necessary to actually realize normalization," Blinken told a Senate committee.

"Because that requires an end to (the war in) Gaza and that requires a credible pathway to a Palestinian state," he said.

Both Netanyahu and then US president Donald Trump have hailed Israel's 2020 normalization with three Arab states -- the United Arab Emirates, Bahrain and Morocco -- as a signature achievement.

US and Israeli leaders see Saudi Arabia as a much bigger prize as the kingdom is the guardian of Islam's two holiest sites.

But Saudi Arabia, in return for a deal, wants progress on a Palestinian state -- an idea resisted by years by Netanyahu.

The kingdom also wants alliance-style security guarantees from the United States, which has long sought but struggled to reduce its Middle East footprint, as well as possible civilian nuclear cooperation.

On the US-Saudi negotiations, Blinken said, "I think we're at a point now where those agreements are very much within reach -- very close reach."

Biden's push with Saudi Arabia comes despite criticism of the kingdom from parts of his Democratic Party and the president's own promise as a candidate to treat Crown Prince Mohammed bin Salman as a "pariah" due to his human rights record.

Republican Senator Lindsey Graham -- a close ally of Trump, who is seeking to return to the White House in November elections -- acknowledged that Congress may be more likely to approve a US-Saudi deal with Biden as president.

"I think this needs to be done on your watch," Graham told Blinken.

"As a Republican, I think most of my colleagues would embrace a security agreement between the United States and Saudi Arabia if it would lead to normalization and a brighter future for Israel and the Palestinians," he said.

Graham urged Israel "not to let this moment pass."

"To my friends in Israel, I will never abandon your security, but we're going to have to sit down as a world and make some hard decisions," he said.