Crude-oil futures extended losses in Asian hours Friday due to an uncertain demand outlook that has kept oil prices choppy throughout the trading week.
On the New York Mercantile Exchange, light, sweet crude futures for delivery in April traded at $101.99 a barrel at 0624 GMT, down $0.41 in the Globex electronic session. April Brent crude on London's ICE Futures exchange fell $0.21 to $108.75 a barrel.
Both Nymex WTI and Brent crude fell overnight and have settled lower for two of the past three sessions, after a strong rally last week.
The easing of strong winter demand in the U.S., warmer temperatures in Europe and worries over China's sustained economic growth are together weighing on crude-oil prices.
"It's also probably worth bearing in mind that the global supply/demand balance typically swings to a surplus for the second quarter, when global demand is at its weakest for the year," Tim Evans, energy futures specialist at Citi Futures said in a note.
Financial markets will look to China's official manufacturing purchasing managers' index for February, due on Saturday, for indications of economic growth in the world's second-largest oil consumer.
On Thursday, U.S. Federal Reserve Chairwoman Janet Yellen acknowledged weaker economic data was due to the winter season and said the reduction of its monthly bond purchases may be reconsidered if the economic outlook changes significantly.
The Fed's bond purchases have supported commodity markets.
The premium of Brent over WTI is at $6.78 a barrel, having narrowed to its lowest in four-and-a-half months.
Oil supply from the Organization of Petroleum Exporting Countries fell to its lowest level in two years in February, led by declines in Libya and Saudi Arabia, with a drop of around 11,000 barrels a day to an average of 28.87 million barrels, ANZ said citing market reports.
Traders are also monitoring the crisis in Ukraine that may make oil prices vulnerable if Russian Urals crude supply to Europe is affected.
Nymex reformulated gasoline blendstock for March--the benchmark gasoline contract--fell 54 points to $2.7564 a gallon, while March heating oil traded at $3.0800, 65 points lower.
ICE gasoil for March changed hands at $918.00 a metric ton, down $0.25 from Thursday's settlement.
