West Texas Intermediate futures for January delivery plunged to $40.64 (-3.01%), while Brent crude fell to $43.76 (-2.02%) amid persisting oversupply concerns.

Industry group Baker Hughes reported on Friday that the U.S. oil rig count fell by 10. However market participants are focused on the existing supply glut, which may worsen when Iran adds more crude to the market.

The Organization of the Petroleum Exporting Countries is set to meet on December 4 in Vienna. However it is widely expected that the member countries, led by Saudi Arabia, will stick to their current policy and will not reduce output in order to support prices.