Both contracts sank Friday after a report showed the number of active US installations rose for a fourth straight week as firms are tempted to reopen them by the relatively higher prices.
However, the increase in production adds to an already painful oversupply crisis. "Crude oil markets have been under pressure as oil supplies have started growing with the resumption of output from the capacity lost due to wildfires in the Canadian oil sands," EY oil and gas head Sanjeev Gupta said in a note, referring to blazes that hit the country's key oil fields.
Canada is the largest supplier of crude to the United States. Gupta said media reports of increased production from Iraq have also added to market pressure.
At about 0300 GMT, US benchmark West Texas Intermediate was down six cents at USD 44.13 a barrel and Brent was also six cents lower at USD 45.63. Official US data last week showed that while crude supplies decreased, gasoline supplies remained high even during the crucial summer holiday driving season.
"The general tone for the market at the moment is soft to sideways," Ric Spooner, a chief analyst at CMC Markets in Sydney, told Bloomberg News.
"It's being weighed down by US dollar strength against a background of relatively high inventories and the fact the rig count has begun to creep up."
The dollar has picked up in recent weeks as central banks around the world prepare to unveil fresh stimulus measures at the same time as strong US data fuel speculation the US Federal Reserve will lift interest rates.
Prices have fluctuated between USD 43 and USD 52 per barrel since early June after falling below USD 30 in February on the back of the world supply glut and weak demand.
