The drone attack during the night towards Saturday knocked out half of Saudi Arabia's oil production. This corresponds to five percent of the world's oil production - and now, as expected, effects on crude oil prices are expected.

During Sunday, Brent Crude crude oil prices rose 19 percent in London. At the same time, prices rose by 15 percent in the United States.

The price of North Sea oil is also rising since trading began at midnight Swedish time. The price first increased by 18 percent and then went down slightly and stabilized at an increase of about 12 percent compared to Friday, according to TT.

Trump opens oil reserves

Saudi state oil company Saudi Aramco has not yet said when oil production could return to normal. A source tells Reuters it is expected to be weeks rather than days before production is restored. And now Donald Trump promises to open US oil reserves to shut down the market.

"I have approved that oil be taken from the strategic oil reserve, if needed, in an as yet undetermined amount but sufficient to keep the market well-stocked," he writes on Twitter.

He also writes that he has called on the authorities to speed up decisions regarding new oil pipelines.

Awaiting reply from Saudi Arabia

The Huthi rebels in Yemen have taken on the attack, but US Secretary of State Mike Pompeo wrote on Saturday that Iran is behind it instead. That statement now seems to be trying to mitigate Donald Trump.

"There is reason to believe we know who is guilty," he writes on Twitter.

He continues:

"But we are waiting to hear from the Kingdom (Saudi Arabia, ed.) About who they believe is behind the attack and how we should proceed."

Iran has denied that they have anything to do with the attack.

“Such worthless accusations…. are meaningless, incomprehensible and pointless, ”said Abbas Mousavi, spokesman for Iran's foreign ministry, in a statement according to the Reuters news agency.