Crude oil prices continued to slide on Tuesday, reaching new five-and-a-half year lows, amid concerns that a global supply glut could intensify.
Brent crude fell by 3%, dipping below $52 a barrel, after the world's top producer Saudi Arabia slashed prices to its European customers late on Monday.
The Saudis have maintained production throughout the collapse in oil prices, suggesting that the Kingdom is intent on maintaining its market share and can afford to cope with lower prices in the short term.
The Saudi move came after Russia and Iraq, two of the world's bigger producers, reported no sign of trimming output.
Russia reported a post-Soviet high output in December while Iraq, the second largest producer in the Organisation of the Petroleum Exporting Countries (Opec) cartel, announced plans to ramp up its output to a record high this month.
Both Brent and US oil have lost more than half of their value in the past six months.
Meanwhile, concerns over the Greek economy and talk of a slowdown in the Chinese economy have affected demand-side factors.
In a stuttering eurozone economy, Greece is facing weeks of political uncertainty as its population prepares to elect a new government, with an anti-austerity political party currently leading in the polls.
Analysts have also cited slowing demand from China, whose economic growth has shown signs of slowing down in recent months.