Iranian-backed rebels set two major Saudi Arabian oil facilities ablaze with coordinated drone attacks early Saturday, forcing the kingdom to shut down half its oil production and sparking fears of a big jump in oil prices.

The Houthi rebels, locked in a four-year-long war with Saudi-led forces in Yemen, claimed responsibility for the 4 a.m. attack, in which 10 drones hit the Abqaiq refinery, the world’s largest oil-processing facility, and the Khurais oil field.

Secretary of State Mike Pompeo dismissed the Houthis’ claim and blamed Iran for the strike, tweeting, “There is no evidence the attacks came from Yemen.”

President Trump spoke to Saudi Crown Prince Mohammed bin Salman by phone on Saturday and offered US support for Saudi Arabia’s self-defense, the White House said.

Saudi Aramco, the state-owned oil company that operates the facilities, said the fires were brought under control, but it cut oil production back by 5 million barrels a day, or about 5% of the world’s production, to address the damage.

The Houthis have sent drones to attack Saudi oil infrastructure for weeks, but none of the earlier strikes caused as much damage.

“We promise the Saudi regime to expand our operations in future and to be more painful as long as its aggression and siege continues,” said Houthi military spokesman Yahia Sarie. “The only option for the Saudi government is to stop attacking us.”

While Aramco said it hoped to get production back up as soon as Monday, according to The Wall Street Journal, oil prices were still expected to spike when the markets reopen after the weekend, in part because the attack’s success shows Saudi Arabia is vulnerable.

Tensions in the Persian Gulf region were already high. Iran-US relations have unraveled since the US exited the 2015 nuclear deal, and Iran has targeted ships in the vital Strait of Hormuz.

And recent US sanctions have cut Iran’s oil production, reducing the global supply and making the market more vulnerable to disruption.

Although the US is a net exporter of oil, Saudi production has a big impact on global oil prices.

Some analysts suggested oil prices could spike between $5 and $10 a barrel when the markets open Monday, which translates to a jump of 12 to 25 cents per gallon for gas.

Pompeo tweeted that the US “will work with our partners and allies to ensure that energy markets remain well supplied.”

With Post wires