International Benchmark Brent crude fell to $64.69 per barrel while American benchmark West Texas Intermediate WTI saw $61.62 at 09.40 GMT+3 on Thursday.
On Monday, Brent crude traded at $67.19 per barrel while WTI saw $63.78 at 06.40 GMT.
The U.S. Energy Information Administration (EIA) announced on Wednesday that crude oil inventories in the country increased last week.
Commercial crude oil stocks rose by 3 million barrels to reach 423.5 million barrels for the week ending Feb. 23, the EIA data showed.
After the data released, Brent crude fell to as low as $64.50 per barrel on Wednesday while WTI declined to $61.37 a barrel for a daily loss of more than 2 percent.
The U.S.' crude oil production rose 13,000 barrels per day (bpd) to reach 10.28 million bpd for the week ending Feb. 23, the EIA said.
By Gulsen Cagatay