Saudi Arabia could reduce valuable security and intelligence cooperation with longstanding ally Washington after a Congressional "stab in the back" allowing 9/11 victims to sue the kingdom, experts warn.
Cutting such cooperation is among the options available to Riyadh after Congress voted overwhelmingly on Wednesday to override President Barack Obama's veto of the Justice Against Sponsors of Terrorism Act (JASTA).
"I'm afraid that this bill will have dire strategic implications" for the United States, Salman al-Ansari, the president of the Saudi American Public Relation Affairs Committee (SAPRAC), told AFP.
"This partnership has helped provide US authorities with accurate intelligence information" that helped stopped attacks, said Ansari, whose committee is a private initiative to strengthen Saudi-US ties.
JASTA allows attack survivors and relatives of terrorism victims to pursue cases against foreign governments in US federal court and to demand compensation if such governments are proven to bear some responsibility for attacks on US soil.
Saudi Arabia was home to 15 of the 19 Al-Qaeda hijackers who carried out the September 11, 2001 attacks on the United States which killed nearly 3,000 people.
Riyadh denies any ties to the plotters.
The United States and Saudi Arabia have a decades-old relationship based on the exchange of American security for Saudi oil.
Ties between Riyadh and Washington became increasingly frayed under Obama, but analysts said security cooperation and intelligence sharing remained solid.
Whether that will continue, analysts said, is now a question.
"Saudi has been stabbed in the back by this unthoughtful and unrealistic bill," Ansari said. "How can you sue a country that is collaborating against the very same terrorism that they are baselessly being accused of?"
Mustafa Alani, a senior adviser to the Gulf Research Center, suggested a review of the Saudi-US alliance.
"Your financial investments have to be reduced in the US, your political and security cooperation has to be reduced," he said.
A senior Saudi prince reportedly threatened to pull out billions of dollars of US assets if JASTA became law, though Saudi officials have distanced themselves from such threats.
"It will be very difficult for Saudi Arabia to continue in intelligence cooperation when they take such a hostile position," said Jamal Khashoggi, a veteran Saudi journalist and analyst.
He said Saudi officials are probably debating whether to act now or "wait until the first suit is filed in some small town in America".
Khashoggi urged caution however.
"It is important to have the Americans by our side" to face threats in Syria, Yemen, and to counter Saudi Arabia's rival Iran, he said.
The Congressional vote coincides with Western criticism of Saudi Arabia over civilian casualties from its air war against rebels in Yemen, its human rights record, and a fundamentalist Muslim ideology accused of fuelling violent Sunni extremism.
Khashoggi said Saudi Arabia must "look inside our own system, our own way of thinking" and find a way to remove the kind of perceptions which led to the overwhelming Congressional vote.
Obama opposed the law, saying it would harm US interests by undermining the principle of sovereign immunity, opening up the US to private lawsuits over its military missions abroad.
The erosion of sovereign immunity is also a concern among the six-nation Gulf Cooperation Council, of which Saudi Arabia is the most powerful member.
Saudi Arabia's Gulf allies have lined up beside Riyadh to criticise the law.
United Arab Emirates Foreign Minister Sheikh Abdullah bin Zayed al-Nahyan warned before the vote that the law "will have negative effects on international cooperation in the fight against terrorism."
Bahrain's Foreign Minister Sheikh Khaled bin Ahmed al-Khalifa said on Twitter on Thursday that the law "is an arrow launched by the US Congress at its own country".
He asked: "Are there no rational people among you?"
Still, Alani and others said they were not sure the Saudi government would be willing to immediately take steps that would jeopardise such a deep-rooted relationship.
"It's not easy to have a U-turn," he said.