Oil prices dived this evening after official figures revealed an unexpected rise in crude stockpiles in the US, the world's biggest energy consumer. US crude slumped $3.50 to $133.50 a barrel, while Brent North Sea crude tumbled $3.46 to $133.
The US Department of Energy said that stockpiles of crude had risen for the first time in six weeks, by 800,000 barrels, in the week to June 20. Analysts had expected a drop of 1.1 million barrels.
Oil prices have almost doubled over the past year after striking record highs of close to $140 last week. Saudi Arabia, the world's largest exporter, agreed at the weekend to raise its daily output by more than 200,000 barrels to 9.7 million.
But OPEC president Chakib Khelil and other oil producers are opposed to higher output, blaming rocketing prices on speculative buying by funds.
