“Abqaiq is perhaps the most critical facility in the world for oil supply. Oil prices will jump on this attack,” Jason Bordoff, founding director of the Center on Global Energy Policy at Columbia University, said in a statement.

US Secretary of State Mike Pompeo pinned the attack directly on Iran, which backs the Houthi rebels. “Iran has now launched an unprecedented attack on the world’s energy supply. There is no evidence the attacks came from Yemen,” he said on Twitter.

The development comes as Saudi Aramco takes steps to go public in what could be the world’s biggest IPO. Aramco attracted huge interest with its debut international bond sale in April. It commissioned an independent audit of the kingdom’s oil reserves and has started publishing earnings. Over the past two weeks, the kingdom has replaced its energy minister and the chairman of Aramco.

Saudi Arabia, the world’s largest oil exporter, has cut back on production of crude and other energy products as part of an OPEC effort to boost prices. Saudi Arabia produces approximately 10% of the total global supply of 100 million barrels per day.

The International Energy Agency, or IEA, said on Saturday it was monitoring the situation in Saudi Arabia. “We are in contact with Saudi authorities as well as major producer and consumer nations. For now, markets are well supplied with ample commercial stocks,” it said on Twitter.

If the disruption in Saudi Arabia is prolonged, “sanctioned Iran supplies are another source of potential additional oil,” Bordoff said. “But [US President Donald] Trump has already shown he is willing to pursue a maximum pressure campaign even when oil prices spike. If anything, the risk of tit-for-tat regional escalation that pushes oil prices even higher has gone up significantly.”

US Energy Secretary Rick Perry “stands ready” to tap the country’s Strategic Petroleum Reserve to steady oil markets if necessary, a department spokesperson said in a statement. The country’s emergency oil supply — a series of storage tanks and underground caverns created after the oil crises of the 1970s — holds 630 million barrels of crude, an Energy Department official said.

Oil prices fell on Friday, with Brent crude, the global price benchmark slipping 0.3% to close at $60.22 per barrel.