Washington (dpa) - Following drone strikes on the largest oil refinery in Saudi Arabia, the US is ready to free up oil reserves in the event of bottlenecks. This could be counteracted any disruptions of the oil markets, said the spokeswoman for the US Department of Energy, Shaylyn Hynes, with. The largest oil refinery in Saudi Arabia had been attacked with drones over the weekend. The attacks have led, according to official information from Riyadh, to a slump in production.