LONDON (MarketWatch) — Crude oil prices sank to a four-and-a-half year low on Thursday, on news that OPEC has kept its production levels unchanged. Hopes for a cut in output had all but faded after a Saudi Arabian oil minister’s comments a day prior.

Extending losses on the New York Mercantile Exchange, light, sweet crude futures for delivery in January CLF25, sank to as low as $67.75 a barrel during European afternoon trading hours, touching the lowest level since May 2010. The contract was down $4.58, or 6.2%, at $69.11 a barrel at the latest.

January Brent crude UK:LCOF5 on London’s ICE Futures exchange fell $4.71, or 6.1%, to $73.04 a barrel.

U.S. physical trading for oil markets is closed for the Thanksgiving holiday, but products will resume trading at 6 p.m. Eastern Time.

The Organization of the Petroleum Exporting Countries met in Vienna, with the members deciding to keep the group’s production target unchanged. In the runup to the decision, there was speculation the organization might cut production to remove some of the glut in supply in global markets and boost oil prices.

Hopes for an output cut faded on Wednesday, however, when Saudi Arabian oil minister Ali al-Naimi said he expects the market “to stabilize itself eventually,” hinting he wouldn’t push for a cut in OPEC’s production targets.

The 12-member oil cartel typically steps in to adjust output when prices move sharply due to excess or insufficient supply. It currently has an oil production ceiling of 30 million barrels a day and has been producing in excess of this level in recent months. Read: A brief, wondrous history of OPEC landmark events

Crude-oil prices have plummeted this year, losing around 30% of their value since June. This is mainly due to rising U.S. oil production, driven by the shale boom, and slowing demand growth in Asia and Europe.

Analysts say that OPEC would have needed to cut oil production much lower than its current ceiling for prices to make a significant recovery. The decision on production cuts is likely to set the tone for oil prices for the next few months and well into 2015.

Elsewhere in the energy complex, gasoline US:RBF5 for January tanked 5.6% to $1.90 a gallon, while heating oil for the same month US:HOF5 slid 4.4% to $2.22 a gallon.