Oil prices rose on Friday due to Venezuelan political turmoil, which threatens to curb crude oil supply, but worries about rising fuel stocks in the United States and global economic problems have affected morale.
The United States said on Thursday it could impose sanctions on Venezuela's exports after opposition leader Juan Guido was recognized as a temporary president this week, prompting President Nichola Maduro to break his ties with Washington.
But the trade dispute between the US and China and the pessimism of world economic growth have cut prices.
Brent oil futures closed at $ 61.64 a barrel, down 55 cents or 0.9 per cent. But Brent lost 1.7% since early Monday for the first weekly loss in four weeks.
The US oil settlement price was set at 53.69 dollars a barrel, which is 56 cents, or 1.05 per cent. Crude oil prices dropped by about 0.2% over the week, also marking their first weekly four weeks fall.
RBK Europe expects any US sanctions to increase the projected reduction of Venezuela's production to almost two-thirds.
"Venezuelan production will drop another 300 to 500,000 barrels a day this year, but such punitive measures could increase this shortfall by several hundred thousand barrels," she said.
Some analysts, however, ruled out the possibility of immediate sanctions.
"We believe the possibility of imposing sanctions on imports from Venezuela is a weak prospect and a final measure will probably not happen weeks or even months if it happens," said Jim Ritterbusch, president of Ritterbusch & Associates.
"Venezuela's development may delay the test that we expect to support at $ 50."