Meanwhile, Donald Trump gave orders to 'substantially increase' sanctions on Iran while Saudi Arabia said the drones came from Iran.
Saudi Arabia showed remnants of what they say are Iranian drones and cruise missiles used in the attacks on an Aramco oil facility on Saturday.
A Saudi defence ministry spokesman said the attack "did not originate from Yemen despite Iran's best efforts to make it appear so".
Iran-aligned Houthi rebels, who are involved in a war against a Saudi-led coalition in Yemen, claimed the attack, but US Secretary of State Mike Pompeo said afterwards that there was "no evidence the attacks came from Yemen".
US officials have said that Tehran is behind the attack which significantly cut Saudi Arabia's crude oil output and resulted in surging oil prices on Monday.
Iran's government has denied responsibility.
Donald Trump tweeted on Wednesday that he instructed the Treasury Secretary to "substantially increase" sanctions on Iran. Trump then told reporters that the US would add "very significant sanctions onto Iran" within the next 48 hours.
The Treasury Department did not immediately respond to a request for comment on the sanctions.
Iranian Foreign Minister Javad Zarif tweeted in response that Trump was "escalating" the "economic war" on Iranians.
Tensions between Iran and the U.S. have risen since the Trump administration increased economic sanctions on the country as part of a "maximum pressure" policy against the regime.
US Secretary of State Mike Pompeo met with Saudi Crown Prince Mohammad Bin Salman on Wednesday, telling reporters: "The Saudis were the nation that were attacked. It was on their soil. It was an act of war against them directly."
"This is the predictable result of Saudi Arabia's continued fighting really with Iran in a proxy war in Yemen," Daniel Davis, a senior fellow with think tank Defense Priorities said. "And as long as these things continue on these kinds of retaliatory strikes are probably going to continue."
_Watch: __Dr Jessie Moritz, an expert in Middle Eastern Political Economy from the Australian National University in Canberra says the question of where the weapons were fired from is the contentious issue: _