By Noah Browning
Benchmark Brent oil were down 71 cents, or 1.14 percent, to $61.39 a barrel at 1445 GMT.
U.S. West Texas Intermediate (WTI) crude fell $1.19 cents or 2.26 percent to $51.53.
"Oil prices are still trying to figure out what lead to follow. On the one hand, there is the OPEC+ cut story, now coupled with increasing issues around Venezuelan supply", Vienna-based consultancy JBC Energy said.
"At the same time, it has to be argued that a lot of the economic data that has been released over the last few days has really not been too encouraging, and U.S.-Chinese trade talks are also seemingly not progressing very fast."
Energy firms in the United States last week increased the number of oil rigs operating for the second time in three weeks, pointing to a further rise in U.S. crude production, a weekly report by Baker Hughes said on Friday.
WTI prices were also weighed down by the closure of the second largest crude distillation unit (CDU) at Phillips 66's Wood River, Illinois, refinery following a fire on Sunday.
Trade talks between Washington and Beijing resume this week with a delegation of U.S. officials travelling to China for the next round of negotiations.
The United States has threatened to increase tariffs already imposed on goods from China on March 1 if the trade talks do not produce an agreement, a move which could help slow growth in fuel demand.
U.S. President Donald Trump said on Thursday he did not plan to meet with Chinese President Xi Jinping before the March 1 deadline, dampening hopes of a quick trade pact.
Prices have been buoyed, however, by output curbs from the Organization of the Petroleum Exporting Countries and its allies, including Russia, a group known as OPEC+.
The deal, effective from January, aims to cut 1.2 million bpd until the end of June to forestall an overhang, in a move producers and many analysts expect to soon help balance supply and demand.
Suhail Al Mazrouei, the Energy Minister of the United Arab Emirates, said on Monday the oil market should achieve this balance in the first quarter of 2019.
OPEC and its allies meet on April 17 and 18 in Vienna to review the agreement, but a draft cooperation charter seen by Reuters fell short of a new formal alliance among the producers.
U.S. sanctions on Venezuela, along with older sanctions on fellow OPEC member Iran, have also prevented crude prices from falling further.
(Reporting by Noah Browning; editing by Emelia Sithole-Matarise; Additional reporting by Henning Gloystein; Editing by Edmund Blair and Mark Potter)
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)