The Houthis attacked two plants at the heart of Saudi Arabia’s oil industry, including the world’s biggest petroleum processing facility, in a pre-dawn strike that several sources said had disrupted output and exports. Foreign Office minister Andrew Murrison described the attacks as “totally unacceptable”.
He tweeted: “Totally unacceptable attack on oil facilities in Saudi Arabia this morning.
“The Houthis must stop undermining Saudi Arabia’s security by threatening civilian areas and commercial infrastructure.”
The attacks, which Houthi commanders said featured 10 drones, follow earlier cross-border attacks on Saudi oil installations and on oil tankers in Gulf waters.
Fire and smoke were still visible hours after the strikes but have now started dying down.
Video footage showed fierce flames and thick plumes of smoke rising towards the dark pre-dawn sky.
There have been no official reports of casualties but witnesses said at least 15 ambulances were seen in the area shortly after the attacks and there was a heavy security presence around Abqaiq.
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Saudi Arabia, leading a Sunni Muslim military coalition that intervened in Yemen in 2015 against the Houthis, has blamed regional rival Shi’ite Iran for previous attacks, which Tehran denies.
Riyadh accuses Iran of arming the Houthis, a charge denied by the group and Tehran.
It was the latest in a series of Houthi missile and drone strikes on Saudi cities that had largely been intercepted, but have recently hit targets, including Shaybah oilfield last month and oil pumping stations in May.
The violence is hampering UN-led peace efforts to end the Yemen war which has killed tens of thousands and pushed millions to the brink of famine.
The conflict is widely seen as a proxy war between Saudi Arabia and Iran.