Crude futures slumped again in Asian trade on Wednesday, with U.S. oil dropping more than 3 percent toward $27 a barrel and its lowest since 2003, on worries about global oversupply.
That came after the International Energy Agency, which advises industrialized countries on energy policy, warned that oil markets could "drown in oversupply" in 2016.
The crash hammered Asian stock markets with MSCI's broadest index of Asia-Pacific equities outside Japan .MIAPJ0000PUS falling 2.8 percent to a four-year low.
"Oil prices are at a level where OPEC countries are all struggling. They are selling oil for cash flow not for profit," said Jonathan Barratt, chief investment financial officer at Sydney's Ayers Alliance.
"U.S. producers are holding out, but I think they're bleeding as well," he said.
U.S. crude futures CLc1 were trading down 97 cents at $27.49 a barrel, or 3.4 percent, at 8:00 GMT, the lowest since September 2003.
The contract settled down 96 cents, or 3.26 percent, the session before.
The expiry of the February contract on Wednesday was "probably" adding further downward pressure on U.S. West Texas Intermediate oil as traders closed positions, said Michael McCarthy, chief market strategist at Sydney's CMC Markets.
Brent futures LCOc1 dropped 60 cents to $28.16 a barrel, or 2.1 percent, not far from the 12-year low hit on Monday. It settled up 21 cents, or 0.7 per cent, in the previous session.
McCarthy said the market had already taken into account the 500,000 barrels per day Iran has forecast it will add to global production.
"(Iran) is really another strike in the same beating the market has taken," McCarthy said.
U.S. commercial crude oil stocks were forecast to have risen by 3 million barrels last week, a preliminary Reuters survey taken ahead of weekly inventory data, showed on Tuesday.
Stocks data from industry group the American Petroleum Institute is due out later on Wednesday. Official data from the U.S. Department of Energy's Energy Information Administration will be out on Thursday, a day late due to a public holiday.
Ample storage space for crude around the world, including 230 million barrels of new storage to be completed this year, will help prevent further sharp price falls but will weigh against significant price rises, according to analysts and industry watchers.
Global financial markets seem to be overreacting to falling oil prices and the risk of a sharp downturn in China's economy, Maurice Obstfeld, the International Monetary Fund's chief economist said on Tuesday.