New York's main contract, West Texas Intermediate light sweet crude for delivery in July, dropped 58 cents to USD 93.70 a barrel in the morning and Brent North Sea crude for July delivery shed 47 cents to USD 102.13.
"Oil prices are being kept down after the US dollar strengthened," Ric Spooner, chief market analyst at CMC Markets in Sydney, told AFP.
A stronger greenback makes dollar-priced oil more expensive for buyers using weaker currencies. In turn, that tends to weigh on oil demand and prices.
But he said any tapering off could only happen once it had confidence that economic gains could be sustained, warning that a "premature tightening of monetary policy" could derail the economic recovery.
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The Fed, the US central bank, has been on an aggressive USD 85 billion a month bond-purchase programme, known as quantitative easing, as part of measures to boost the economy.
Meanwhile, a lighter-than-expected drop in US crude stockpiles was also weighing on prices.
The data indicated weaker demand ahead of the US summer driving season when Americans take to the roads for their holidays.
"The reality is that US crude inventory remains high, indicating weak demand as the driving season approaches," said Spooner.