Oil came under pressure on Wednesday as a resurgent dollar weighed on crude prices ahead of inventory data expected to show whether fuel demand was accelerating with the peak U.S. driving season under way.
U.S. crude closed down 52 cents, or 0.9 percent, at $57.51 a barrel, having seesawed between negative and positive territory throughout the session.
North Sea Brent crude was down $1.70, or 2.60 percent, at $62 a barrel, after rising nearly $1 earlier in the session.
The American Petroleum Institute (API), an industry group, will issue estimates on crude and oil products in storage at 4:30 p.m. EDT ahead of Thursday's official data from the U.S. government.
Analysts polled by Reuters forecast on the average a 2 million barrel draw in crude stocks last week, marking a fourth consecutive week in inventory declines. But some traders think crude stocks may have actually risen last week even as demand for gasoline picked up.
"If you're looking for a catalyst for price recovery from this data, you may not really get it, and that's why the dollar's been exerting it's strength over oil," said John Kilduff, a partner at New York-based commodities fund Again Capital.