The selloff in global oil markets showed little signs of slowing in the new year, falling as much as 6 percent on Monday to their lowest since spring of 2009 as fears of a supply glut that vexed the market for the past six months deepened.
U.S crude closed down $2.65, or 5 percent, at $50.04 a barrel—its lowest settlement since April 2009. The contract fell further in extended trading.
Front-month Brent crude hovered around $53 a barrel, down about $3, after dropping to $52.66, its lowest since May 2009.
U.S crude dipped below $50 a barrel while benchmark Brent crude tumbled under $53 after data showed Russian oil output at post-Soviet era highs and Iraqi oil exports at near 35-year peaks.
U.S. driller ConocoPhillips added to the bearish sentiment, announcing it had struck first oil at a Norwegian North Sea project.
Top crude exporter Saudi Arabia has made deep cuts to its monthly oil prices for European buyers, a move that analysts said reflects the kingdom's deepening defence of market share. Saudi Arabia also trimmed prices for U.S. refiners while raising rates for Asia.
The euro's tumble to 2006 lows, and slower-than-expected growth in U.S. manufacturing, completed a perfect storm for the bearish oil markets.
"There's no doubt that we have a combination of supplies hitting their zenith at a time when demand is weakening," said Phil Flynn, analyst at Price Futures Group in Chicago.