Crude oil prices retreated further in Monday trading after Saudi Arabia again defended its insistence on keeping production levels static.

Oil prices have shed close to half of their value since June as markets became skewed toward the supply side. U.S. oil production is around 9 million barrels per day, while imports into North America are in decline. That, coupled with weak demand elsewhere in the world, has pushed oil prices to their lowest point in roughly five years.

The Organization of Petroleum Exporting Countries in November opted to keep production static at around 30 million barrels per day, saying it wanted the market, and not producers, to determine the floor price for crude oil.

Markets since then have shed about 17 percent of their value. In interviews published by a variety of media outlets Monday, Saudi Oil Minister Ali al-Naimi said his country, seen as the most influential figure in OPEC, was going to keep its production levels static.

Last week, he confirmed to the official Saudi Press Agency the country was taking action to maintain its current position in the global oil marketplace.

Brent, the global benchmark price for crude oil, lost 1 percent from the previous session to trade at $60.65 early Monday for the February contract. The January contract dipped below the $60 mark last week before recovering briefly on positive economic news from China.

West Texas Intermediate, the U.S. benchmark, fell 1.6 percent to near $56 per barrel. WTI prices are at a point where some producers working in shale basins in the United States are struggling to make a profit.

OPEC's move was seen by some as a market maneuver meant to push shale producers out of the game. The Saudi oil minister said there were no such conspiracies at work.