The kingdom's oil production has dropped by 5.7 million barrels a day after Saturday's drone strikes on two processing facilities. As Riyadh and Washington point the finger at Tehran, the price of oil is set to rise.
Iran-backed Houthi rebels, fighting against a Saudi-led coalition in neighboring Yemen, claimed responsibility for "a large-scale operation involving 10 drones" against the Abqaiq and Khurais oil facilities run by the Saudi state-owned oil company, Aramco.
"Any attack on Saudi Arabia is sure to shake oil markets because they currently hold the majority of spare crude production capacity," warned Bernadette Johnson, vice president of market intelligence at energy analysts Enverus.
She said if the production cut was prolonged, "we should expect to see a big jump in price until the fields return."
The financial channel CNBC cited several energy analysts as saying that oil prices could immediately spike by $5-$10 when markets reopen on Sunday night (US time), while other commentators predicted $100 (€90) per barrel of oil. On Friday, Brent crude traded at $60.22 a barrel.
Saturday's attacks caused no casualties but forced a suspension of production at the two plants, where extensive damage was reported from huge explosions triggered by the unmanned aircraft.
However, the Paris-based International Energy Agency (IEA) played down the impact of the production cut, which equals 5% of global oil supply.
"For now, markets are supplied with ample commercial stocks," the IEA said in a statement on Saturday.
Aramco said it would take 48 hours to give an accurate assessment of when production could be restored.
Riyadh and Washington quickly blamed Iran for the drone strikes, and US Secretary of State Mike Pompeo insisted there was no evidence the attacks were launched from Yemen.
Washington's chief diplomat labeled the incidents as an "unprecedented attack on the world's energy supply."
His condemnation threw doubt on expectations of a meeting between US President Donald Trump and Iranian President Hassan Rouhani at the upcoming United Nations assembly, which was hoped to calm spiraling tensions between the archfoes in recent months.
Riyadh vows response
Saudi Arabia's Crown Prince Mohammad emphasized the country's "willingness and strength to thwart such a terrorist aggression and deal with its consequences," according to a statement carried by state news agencies.
Yemen's Houthi rebels have carried out a spate of cross-border missile and drone attacks targeting Saudi air bases and other facilities in what they say is retaliation for a long-running Riyadh-led bombing campaign on rebel-held areas in Yemen.