International benchmark Brent crude dropped to $65.55 per barrel while American benchmark West Texas Intermediate (WTI) saw $61.77 at 07.32 GMT on Thursday.
Brent fluctuated last week at around $70, but decreased slightly on Friday to $69.50 per barrel while WTI saw $65.80 at 11.26 GMT.
Crude production in the U.S. hits its highest level ever and surpassed that of Saudi Arabia, the world's biggest crude producer, according to data released Wednesday.
Th U.S. output increased by 332,000 barrels per day (bpd) to 10.25 million for the week ending Feb. 2, the Energy Information Administration (EIA) data showed.
The nation’s previous high crude output was in November 1970 when it averaged just above 10.04 million bpd, according to the EIA.
The U.S.'s crude production last week overtook Saudi Arabia, whose output averaged 9.92 million bpd in December, according to the latest data based on OPEC's Monthly Oil Market Report released on Jan. 18.
By Gulsen Cagatay