International benchmark Brent crude decreased to $61.25 while American benchmark West Texas Intermediate (WTI) saw prices at $55.94 at 0626 GMT on Thursday.
On Monday this week, Brent traded at $63.43 per barrel while WTI reached $58 barrel at the same time.
The main reason for the decrease was put down to rumors of divisions among the Organization of the Petroleum Exporting Countries (OPEC) members who did not want to extend the oil cut decision that was taken on Thursday, Nov. 30.
At the meeting, OPEC and non-OPEC oil producing countries agreed to extend their oil production cut for a further nine months to the end of 2018.
OPEC members on Nov. 30 last year unanimously agreed to lower oil production by 1.2 million barrels per day (bpd) down to 32.5 million bpd. The agreement became effective on Jan. 1, 2017. With the newly signed agreement, the extension will continue up to the end of 2018.
The previous agreement is the first production cut by the organization in eight years, and its first intervention in the global oil market since mid-2014 when oil prices began to fall.
In addition, the U.S.' crude oil production increased for the seventh week in a row last week, according to the country's Energy Information Administration (EIA) data on Wednesday.
Crude production rose by 25,000 barrels per day (bpd) to reach a little over 9.7 million bpd for the week ending Dec. 1, the EIA data showed, putting further downward pressure on prices.
By Gulsen Cagatay
Anadolu Agency
energy@aa.com.tr