Crude oil prices tumbled Thursday on fresh news of U.S. economic weakness and a pledge by 28 countries to release 60 million barrels of oil from strategic reserves.
On the New York Mercantile Exchange, light, sweet crude for August delivery fell almost $5 a barrel to around $90.51 a barrel. Oil's most recent high was $113.93 a barrel in April.
The International Energy Agency, based in Paris, warned that the tight oil market "threatens to undermine the fragile global economic recovery" by forcing individuals and businesses to spend more on energy and less on other goods and services.
It said it made the move because normal increase in demand over the summer "will exacerbate the shortfall further" and pledges by some oil producers to boost ouput will take a while to have an effect.
The 28 members of the IEA — mainly oil-importing countries in Europe — will make 2 million barrels a day available from their emergency stocks over an initial period of 30 days.
Months of fighting in Libya have removed 132 million barrels of light, sweet crude oil from the market by the end of last month, the agency estimated.
Prices have been high in recent months. They eased this week, to below $93 a barrel on Thursday, due to concerns that U.S. economic growth and crude demand will weaken. Demand growth in China, the world's second-largest oil consumer, has also slipped slightly but remains robust.