 "Oil extends rout as economic worries mount")
Brent crude fell to near four-year lows on Thursday and US oil lost more than a dollar as growing concerns over the global economy stretched a four-month rout.
Brent has lost more than 28% since June amid slow demand and abundant supply, with losses accelerating in recent weeks on signals that the Organization of the Petroleum Exporting Countries will not slash output to rescue prices.
Brent crude for November delivery was down 81 cents at $82.97 a barrel by 0450 GMT, its lowest mark since November 2010. The contract expires on Thursday.
US crude fell $1.03 to $80.75 a barrel. It fell to as low as $80.01 in the previous session, its weakest since June 2012.
Global economic worries deepened this week after China's consumer inflation fell to near five-year lows and US producer prices declined for the first time in more than a year, sparking a sell-off in risk assets.
The economic concerns are helping to accelerate losses in oil prices which have been hit hard by a global supply glut.
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The glut in the Atlantic Basin has helped fuel the collapse in oil prices, said Mark Keenan, head of commodities research in Asia for Societe Generale in Singapore.
"That's been well documented and well understood but it nevertheless is still a strong issue," he said.
The International Energy Agency this week cut its oil demand growth forecast for 2015 as global economies remain weak, with chief analyst Antoine Halff saying some OPEC members might prefer to keep selling at lower prices than lose their market.
Venezuela is calling for an emergency meeting of OPEC - ahead of its next scheduled gathering on Nov. 27 - to halt the slide in oil prices.
"Concerns over weak demand continue to pervade, with weakness likely to persist until signs that the supply side is reacting," Australia and New Zealand Banking Group analysts said in a note.
US crude inventories rose 10 million barrels in the week to Oct. 10 to 370.7 million barrels, data from industry group the American Petroleum Institute showed on Wednesday.
This was far higher than analysts' expectations for an increase of 2.8 million barrels.