Oil prices surged to a record high above $135 a barrel early on Thursday, having rocketed by more than $4 a barrel on Wednesday.
US light, sweet crude for July delivery reached $135.09, taking its gain for the year so far above 40%.
The main driver was the weekly US crude stocks figure, which showed a 5.4 million barrel fall, when a small increase had been expected, BBC reports.
The continuing weakness of the US dollar also supported prices.
The US Energy Information Administration blamed the fall in its stocks figure on a fall in imports and a pick-up in demand from refineries.
Graph of light, sweet crude prices in 2008
Oil prices have set new records in 10 of the last 14 trading sessions.
"You really cannot forecast how much further the market will rally now," said Tatsuo Kageyama from Kanetsu Asset Management in Tokyo.
"All I can say is the market will continue to rise."
London's Brent crude also set an intra-day high on Thursday, peaking at $134.85 a barrel.
Investors moving money into oil from other areas have also been blamed for rising prices.
"Oil has performed better than equities and bonds," said Victor Shum from the energy consultancy Purvin and Gertz in Singapore.