Oil prices fell more than 6 percent to their lowest level in more than a year, amid fears of oversupply, although two major producers are considering a cut in production.
Oil supplies are growing faster than demand and to avoid a significant increase in unutilized fuel stocks similar to those of 2015, the Organization of the Petroleum Exporting Countries (OPEC) is considering starting production cuts after a planned meeting on December 6.
But this has so far had little impact in support of prices, which have fallen more than 20 percent since the beginning of November, after seven consecutive weeks of losses. Prices are heading towards the biggest monthly drop since late 2014.
Markets are also affected by the trade war between the United States and China, the world's two largest economies and the largest oil consumers.
"The market is taking into account an economic slowdown," Phil Fellin, an analyst at PricewaterhouseCoopers Group in Chicago, told Reuters. "They expect that trade talks with China will not go well," referring to expected talks between US President Donald Trump and his Chinese counterpart, Ping at the G-20 summit next week.
"The market does not think OPEC will be able to move quickly enough to offset the expected slowdown in demand," Flynn said.
Global Brent crude futures fell to $ 3.80, or 6.07 percent, to settle at $ 58.80 a barrel after touching $ 58.41, the lowest level since October 2017.
US benchmark WTI futures closed down $ 4.21, or 7.71 percent, to settle at $ 50.42 a barrel after recording at $ 50.53, also the weakest since October 2017.
Brent ended the week with a loss of more than 11 percent, while US crude fell more than 10 percent.
Market fears grew from weak demand after China said its gasoline exports fell to a one-year low amid abundant supply of fuel in Asia and the world.
Analysts say if OPEC decides to cut output at its meeting next month, oil prices may recover.
US stocks fell with a sharp drop in energy stocks.
US stocks closed lower in a brief session after the Thanksgiving holiday, hurt by a sharp fall in the energy sector as oil prices continued to weaken.
The Dow Jones industrial average <.DJI> was down 178.74 points, or 0.73 percent, to close at 24,285.95. The Standard & Poor's 500 Index <.SPX> was down 17.37 points, or 0.66 percent, to end unofficially at 2,632.56.
The Nasdaq Composite Index <.IXIC> was down 33.27 points, or 0.48 percent, at 6,938.98.
The three indexes ended the week with sharp losses as the Dow fell 4.4 percent, the Nasdaq 4.3 percent and the S & P 3.8 percent.
The Dow Jones and Nasdaq indexes were the biggest weekly drop in percentage terms since March