Oil fell on Tuesday, folding under the weight of a broad stock market sell-off that undercut support to prices earlier in the day from expectations that OPEC will introduce new output curbs.
Brent crude oil futures, the international benchmark for oil prices, were at $66.37 a barrel at 07:52 GMT, down 42 cents, or 0.6 percent, from their last close.
U.S. West Texas Intermediate (WTI) crude futures were at $56.94 per barrel, 23 cents, or 0.4 percent, below their last settlement.
Oil prices are around a quarter below their recent peaks in early October, weighed down by surging supply, especially from the United States, as well as a slowdown in global trade.
U.S. crude oil production has soared by almost 25 percent this year, to a record 11.7 million barrels per day (bpd).
That comes amid widespread market expectations of an economic slowdown, which saw Asian stock markets tumble again on Tuesday, adding to sharp losses on Wall Street the previous day.
Amid the uncertainty, financial traders have become wary of oil markets, seeing further price downside risks from the growth in U.S. shale production as well as the deteriorating economic outlook.
Concerned about an emerging production overhang similar to the one that led to a price slump in 2014, the Organization of the Petroleum Exporting Countries (OPEC) is pushing for a supply cut of 1 million to 1.4 million bpd.