Global oil prices spiralled lower Monday to strike new five-year lows as traders fretted over gloomy data, demand worries and plentiful crude supplies.
In early afternoon London deals, Brent North Sea crude for delivery in February sank to $54.44 per barrel, hitting the lowest level since May 2009.
US benchmark West Texas Intermediate for February sank to a similar low at $51.16.
"Oil endured brand new five-year lows," said analyst Connor Campbell at trading firm Spreadex.
"The commodity has continued to shed points in the New Year, prompted by a cavalcade of bad manufacturing figures across the globe last week.
"The black stuff is still looking abandoned and lost as 2015’s trading begins in earnest, and continues to be a stain on the worldwide markets."
Traders meanwhile awaited fresh leads from top crude consumer the United States, while analysts warned that further losses are  likely.
Singapore's United Overseas Bank said in a commentary that a key US employment report on Friday and the release of the latest meeting minutes from the US Federal Reserve on Wednesday "will dominate the market's attention" this week.
Investors will pore over both releases for fresh clues on when the US central bank will raise interest rates, the Singapore lender said.
Daniel Ang, investment analyst at Phillip Futures in Singapore, said crude prices are expected "to continue to be on (a) bearish trend".
"After what seemed to be profit-taking at the end of the year, oil bears have returned from their holidays and are back for more," he said.
"As we continue to take a bullish stand for the US economy, we expect the dollar to strengthen, thus putting further downward pressure on oil prices."
Crude has lost nearly half its value since June because of a global supply glut, as well as slowing growth in China and emerging market economies, a recession in Japan and a near stall in the eurozone.
The OPEC oil-producing cartel in November said it would maintain output levels despite ample global supplies, in part because of cheaper oil extracted from North American shale rock.