Oil prices sank on Friday as concerns about weak demand growth took deeper hold in the market.
New York's main contract, West Texas Intermediate (WTI) crude for May delivery, fell $2.22 from Thursday to $91.29 a barrel.
In London, Brent North Sea crude for delivery in May finished at $103.11, down $1.16.
"The petroleum markets are breaking to the downside in relatively dramatic fashion on likely long liquidation amid growing concerns about the demand prospects," said Timothy Evans of Citi Futures.
He noted the fall came as part of "what has become a broader commodity sell-off."
"Weak US retail sales and slumping industrial output in Europe, as well as an upcoming downward revision to the GDP outlook from the IMF, have piled on top of this week's downward revisions to oil demand prospects," he said.
The Organisation of Petroleum Exporting Countries (OPEC), the International Energy Agency (IEA) and the US government's Energy Information Administration all downgraded their demand forecasts for 2013 this week.
"All major forecasters painted a similar picture of plentiful supplies and sluggish demand," said VTB Capital analyst Andrey Kryuchenkov