Drone attacks have set alight two major oil facilities run by the state-owned company Aramco in Saudi Arabia, state media say.

What are the facilities?
The Abqaiq plant turns sour crude into sweet crude, producing up to 7 million barrels a day. Aramco says it is the world’s largest “crude oil stabilisation plant”. Saudi security forces foiled an attempt by al-Qaeda to attack the Abqaiq facility with suicide bombers in 2006. The Khurais oilfield came on line in 2009 and is the nation’s second-largest after Ghawar. Khurais reportedly produces 1.5 million barrels a day with estimated recoverable oil reserves of more than 20 billion barrels. Global oil markets are closed for the weekend so there was no immediate effect on prices. The attacks come as Aramco prepares for a much-anticipated initial public offering (IPO), part of a reform package led by King Salman’s son, Crown Prince Mohammed bin Salman, to reduce the economy’s reliance on oil.Who could be behind the attacks?
Houthi fighters were blamed for drone attacks on the Shaybah natural gas liquefaction facility last month and on other oil facilities in May. The Iran-aligned rebel movement is fighting the Yemeni government and a Saudi-led coalition. Yemen has been at war since 2015, when President Abdrabbuh Mansour Hadi was forced to flee the capital Sanaa by the Houthis. Saudi Arabia backs President Hadi, and has led a coalition of regional countries against the rebels. The coalition launches air strikes almost every day, while the Houthis often fire missiles into Saudi Arabia.
Saudi-led coalition air strikes regularly target Houthis in Yemen photo: EPA[/caption]
