Crude oil prices have fallen back toward $100 a barrel, as oil facilities in the Gulf of Mexico were spared by Hurricane Gustav.
US crude touched a five-month low of to $105.46 a barrel, down almost $10 from Friday.
London's Brent crude fell $3.46 to trade at $105.95.
Fears of lower global demand for oil also pressured crude prices.
While still high in historical terms, crude is now significantly Oil prices slip to seven-week low ...
Venezuelan, Colombian leaders meet ... below the record $147 a barrel hit in early July.
Hurricane Gustav had weakened as it hit the US Gulf of Mexico coast south-west of New Orleans. It was downgraded to a tropical storm after hitting Fourchon, a port in Louisiana.
Initial checks by some US refiners reported no damage from Gustav, which had originally been classed as the biggest threat to the sector since devastation from Hurricane Katrina in 2005.
Oil traders speculated that slowing global economic growth will dampen demand for crude, even in booming China and India.
"The market continues to be weighed down by worries of a global economic downturn and slowing oil demand in developing markets," said Victor Shum, an energy analyst with consultancy Purvin & Gertz in Singapore.
Opec, the association of oil producing countries, holds its regular meeting next week in Vienna, and there has been speculation that some of its members, such as Iran and Venezuela, would like it to tackle falling oil prices.
Opec members produce about 50% of the world's oil supply.
(BBC)
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