Oil declined about 5 percent on Tuesday after the International Monetary Fund cut its 2015 global economic forecast on lower fuel demand and key producer Iran hinted prices could drop to $25 a barrel without supportive OPEC action.
U.S. crude, also known as West Texas Intermediate or WTI, settled 4.7 percent lower at $46.39 a barrel, near its intraday bottom of $46.23.
Brent crude was last down about 70 cents at $48 a barrel, after touching a session low at $47.78.
Genscape, an analytics firm that monitors U.S. oil stocks, reported a 2.6 million-barrel build last week in Cushing, Oklahoma, the delivery point for the U.S. crude futures contract, adding to the market's bearish sentiment, traders said.
Trade group American Petroleum Institute will issue its data on U.S. crude inventories for last week on Wednesday while the government's Energy Information Administration will release its stockpile tally on Thursday, both delayed a day by a holiday on Monday.