The price of oil is its highest level since the financial crisis began.
In Europe, Brent crude futures rose to $US91.58 per barrel, while in the United States, West Texas Intermediate hit $US89.35p/b - the highest levels since October 2008.
Among the factors driving prices higher are rising demand because of the global economic recovery and cold weather in Europe, as well as the weak US dollar.
However, the BBC reports prices are still 40% below their pre-crisis peak.
The current oil price is already significantly above the levels experienced prior to 2007.
During 2007-08, a speculative bubble pushed the price of Brent crude to a peak of $US147.50p/b in July 2008.