The pre-dawn strikes on Saturday knocked out more than half of crude output from the world's top exporter - five percent of the global oil supply - and cut output by 5.7 million barrels per day, Al Jazeera has reported.
Yemen's Houthi link rebels, who have been locked in a war with a Saudi-UAE-led coalition since 2015, claimed responsibility for the attacks, warning Saudi Arabia that their targets "will keep expanding".
But US Secretary of State Mike Pompeo swiftly accused Iran link of being behind the assault, without providing any evidence. The claim was rejected link Tehran which said the allegations were meant to justify actions against it.
Saudi Arabia, meanwhile, has promised to "confront and deal with this terrorist aggression", while US President Donald Trump link hinted at possible military action after Riyadh concluded its investigation into the attacks. Trump says 'looks like' Iran responsible for Saudi attacks
Trump said it's "looking like" Iran was responsible for the attacks on key oil installations in Saudi Arabia, but he said he doesn't want war.
Trump said at the White House that the US is not looking at retaliatory options until he has "definitive proof" that Iran was responsible.
Still, Trump told reporters in the Oval Office that the US "is prepared" if the attacks warrant a response. Putin proposes Russian missile defence for Saudi Arabia
Russia is ready to help Saudi Arabia following attacks on the Saudi oil industry if needed, Russian President Vladimir Putin said after talks with leaders of Turkey and Iran in Ankara, and proposed Russian weapons for purchase.
"We are ready to provide respective assistance to Saudi Arabia, and it would be enough for the political leadership of Saudi Arabia to make a wise government decision - as the leaders of Iran did in their time by purchasing S-300 and as (Turkish) President (Tayyip) Erdogan did by purchasing the latest S-400 'Triumph' air defence systems from Russia ," Putin said.
These Russian weapons would protect any infrastructure facilities of Saudi Arabia, he added.