Dubai, United Arab Emirates — Yemen's Iran-backedrebels claimed responsiblity for drone attacks Saturday on two major Saudi oil facilities, sparking huge fires and possibly affecting the global energy supplies. U.S. Secretary of State Mike Pompeo blamed Iran for the strike, calling it "an unprecedented attack on the world's energy supply."
"We call on all nations to publicly and unequivocally condemn Iran's attacks. The United States will work with our partners and allies to ensure that energy markets remain well supplied and Iran is held accountable for its aggression," Pompeo tweeted Saturday afternoon.
It remained unclear hours later whether anyone was injured at the Abqaiq oil processing facility and the Khurais oil field or what effect the assault would have on oil production. Rising smoke from the fires at the sites could be seen by satellites.
The attack by the Iranian-backed Houthis in the war against a Saudi-led coalition comes after weeks of similar drone assaults on the kingdom's oil infrastructure, but none of the earlier strikes appeared to have caused the same amount of damage. The attack likely will heighten tensions further across the Persian Gulf amid an escalating crisis between the U.S. and Iran over its unraveling nuclear deal with world powers.
United Nations envoy Martin Griffiths described the attacks as "extremely worrying" in a statement to BBC News. He called on all parties in the Yemen conflict to exercise restraint.
The first word of the assault came in online videos of giant fires at the Abqaiq facility, some 205 miles northeast of the Saudi capital, Riyadh. Machine-gun fire could be heard in several clips alongside the day's first Muslim call to prayers, suggesting security forces tried to bring down the drones just before dawn.
In daylight, Saudi state television aired a segment with its local correspondent near a police checkpoint, a thick plume of smoke visible behind him.
The fires began after the sites were "targeted by drones," the Interior Ministry said in a statement carried by the state-run Saudi Press Agency. It said an investigation was underway.
Saudi Aramco, the state-owned oil giant, did not respond to questions from The Associated Press. The kingdom hopes soon to offer a sliver of the company in an initial public offering.
In a short address aired by the Houthi's Al-Masirah satellite news channel, military spokesman Yahia Sarie said the rebels launched 10 drones in their coordinated attack after receiving "intelligence" support from those inside the kingdom. He warned that attacks by the rebels would only get worse if the war continues.
"The only option for the Saudi government is to stop attacking us," Sarie said.
The rebels hold Yemen's capital, Sanaa, and other territories in the Arab world's poorest country. Since 2015, a Saudi-led coalition has fought to reinstate the internationally recognized Yemeni government.
The U.S. Embassy in Riyadh said it was unaware of any injuries to Americans. Saudi Aramco employs a number of U.S. citizens, some of whom live in guarded compounds near the site.
"These attacks against critical infrastructure endanger civilians, are unacceptable, and sooner or later will result in innocent lives being lost," U.S. Ambassador John Abizaid, a former Army general, said.
Saudi Aramco describes its Abqaiq oil processing facility in Buqyaq as "the largest crude oil stabilization plant in the world."
The facility processes sour crude oil into sweet crude, then transports it onto transshipment points on the Persian Gulf and the Red Sea or to refineries for local production. Estimates suggest it can process up to 7 million barrels of crude oil a day. By comparison, Saudi Arabia produced 9.65 million barrels of crude oil a day in July.
The plant has been targeted in the past by militants. Al Qaeda-claimed suicide bombers tried but failed to attack the oil complex in February 2006. The Khurais oil field is believed to produce over 1 million barrels of crude oil a day. It has estimated reserves of over 20 billion barrels of oil, according to Aramco.