Oil prices fell Monday in Asia as concern over the US economy drove down regional stock markets and outweighed concern that OPEC will resist pressure to raise crude production levels. Oil prices have now retreated more than $10 from a record above US$100 a barrel early this year on worries a flagging US economy would dampen fuel demand. Prices had gained Friday on hopes that US President George W. Bush's economic stimulus plan would work. But most stock markets have since reacted pessimistically, uncertain Bush's plan is enough to stave off a severe economic downturn in the world's largest oil consumer. Asian markets plunged Monday, with benchmark indices in Hong Kong and China both dropping more than 5 percent. On Friday in the US, the Dow Jones industrials fell 0.5 percent after Bush announced a $145 billion tax relief package. Light, sweet crude for February delivery fell 97 cents to $89.60 a barrel in Asian electronic trading on the New York Mercantile Exchange by late afternoon in Singapore. The contract rose 44 cents to settle at $90.57 a barrel on Friday.