The New York's main contract is light sweet crude for delivery in June, down one dollar to 74.65 dollars per barrel.
Brent North Sea crude oil for June delivery fell 68 cents to 80.52 dollars per barrel.
The European single currency fall sharply against the dollar on Thursday, as traders seek "safe haven" (safe haven), the U.S. currency in the face of mounting debt and deficit concerns the euro zone.
Units of the euro zone sank as low as 1.2540 dollars - is not far from the 14-month low of 1.2529 dollars reached a week ago.
"A weak euro is still burdening prices," said analyst Andrey Kryuchenkov VTB Capital.
Prices rose in Asian trade on Thursday, supported by positive economic data from Europe and the United States, analysts said.
"Oil is trying to find a place where he is, 'said Victor Shum, an analyst with energy consultancy Purvin and globally based Gertz in Singapore.
Price "recalibrating the current environment" in which global markets pondered whether the bailout plan (bailout) the euro zone was sufficient to prevent the spread of financial debt problems arising from Greece.
"If the debt crisis of Europe is stable and subsidies as a result of the bailout package that was announced earlier this week, oil prices likely to recover," said Shum.
European Union and the International Monetary Fund last week approved a rescue package of 750-billion (one trillion dollars) for Greek and other euro zone members with problems.
However, concerns about how the rescue package will be made, reducing the initial euphoria over the deal.
Oil prices traded variated on Wednesday as investors remained skeptical about the bailout plan and U.S. crude stockpiles rose more than expected.
The increase in U.S. energy stockpiles, which indicated weak demand, may limit the increase in oil prices, according to analysts.
The U.S. Energy Department said Wednesday that crude stockpiles rose by 1.9 million barrels last week - more than double analysts expected.
Stock in the main central terminal Cushing, Oklahoma, climbed to a record 37 million barrels from 36.2 million the previous week.
Demand in the United States closely watched by the market because the state of the world's biggest energy consumer.
