 "Oil prices fall near 2003 lows on oversupply, demand worries")
Oil futures have hit their lowest levels since 2003 this week as investors worry that a glut of crude is combining with slowing demand due to economic weakness, especially in China.
Benchmark Brent was down 21 cents at $27.67 a barrel by 1206 GMT. Brent has lost 26% in January, on track for its biggest monthly fall since 2008.
Front-month West Texas Intermediate (WTI) crude futures traded at $28.00 per barrel, down 35 cents from their previous close.
Broad market sentiment remained bearish as producers around the world pump 1 million to 2 million barrels of crude every day in excess of demand, creating a huge overhang of stored oil.
Iran's return to the oil market this month added to the glut, after the lifting of international sanctions aimed at discouraging the country from obtaining nuclear weapons.
"There are worries surrounding demand and oversupply," said Hans van Cleef, senior energy economist at ABN Amro in Amsterdam.
He said weaker demand in the Middle East, which has been hit by lower oil prices, could add fuel to the sell-off and there was little to stop crude falling to $20 per barrel.
Indicating the glut may grow further, Iraq's Oil Minister Adel Abdul Mahdi told Reuters the country's southern region planned to increase output by up to 400,000 barrels per day (bpd) this year to over 4 million bpd.
Concerns are also growing that China's economy could slow further and cut demand in the world's second-largest oil consumer.
"Lower commodity and oil prices reflect weakening demand," HSBC said on Thursday.
Meanwhile, Venezuela has requested that OPEC hold an emergency meeting to discuss steps to prop up oil prices, although delegates from other members of the producer group said such a gathering was unlikely.
Investors will watch for data from the Energy Information Administration at 1600 GMT for more detail on the extent of oversupply in the United States.
Analysts expect crude stocks to have risen by 2.8 million barrels in the week ended Jan. 15, according to a poll of eight analysts.
Data from the American Petroleum Institute, a U.S. industry group, showed crude inventories rose by 4.6 million barrels.
