Oil prices fell on Tuesday, reflecting growing concerns that a two-month rally may be fading, as supply looked set to keep rising and there appeared to be little immediate prospect of demand keeping pace.
Earlier, prices briefly pared losses after Federal Reserve Chair Janet Yellen delivered remarks on the U.S. economy and monetary policy.
Yellen, speaking to Economic Club of New York, noted in prepared remarks that recent readings on the strength of the U.S. economy since the beginning of the year have been mixed.
In fact, Yellen said that only gradual increases in the federal funds rate are likely to be warranted in coming years, and global developments have increased the risks associated with the Fed's economic outlook.
The oil price has risen more than 45 percent since mid-February ahead of a meeting next month of the world's major producers to discuss an output freeze. But there is growing skepticism about the outcome of the meeting.
"Verbal intervention, which has obviously helped the market greatly over the past two months, combined with a production slowdown in the U.S., has probably taken (oil) as far as it can. Now the market really wants to see some action," Saxo Bank senior manager Ole Hansen said.
"We're seeing more and more commentators raise the flag and saying 'have we seen too much, too soon?' in terms of the rally across the sector."