State-controlled Saudi Aramco has shut its 550,000 b/d Ras Tanura refinery on Saudi Arabia's east coast after it was struck by an Iranian drone early on Monday, according to sources with knowledge of the matter.
The facility was "shut down for precautionary measures", the sources said. There were no injuries and the situation is now "under control", they said.
Videos circulating on social media showed large plumes of smoke rising from what appeared to be storage tanks at the site. Aramco has not yet responded to a request for comment.
Ras Tanura is Saudi Arabia's largest refinery and accounts for about 16pc of the kingdom's 3.4mn b/d refining capacity.
The strike comes as the US-Israel conflict with Iran enters its third day, with Iranian missile and drone attacks targeting oil-producing countries across the Mideast Gulf.
Ice Brent crude futures initially rose to $82.17/bl when trading resumed in Asia on Monday. Prices later fell to $75.90/bl before recovering to around $80/bl.
