Oil prices fell on Monday after rising on Friday after renewed fears of shrinking demand in the United States and China, which negatively affected market sentiment.
By 0400 GMT, Brent crude oil futures for January fell 71 cents, or 0.87 percent, to $80.72 per barrel. West Texas Intermediate crude futures for December fell 68 cents, or 0.88 percent, to $76.49 per barrel.
The two crude oils fell below the 100-day average price of $86.61 per barrel for West Texas Intermediate crude and $82.31 per barrel for Brent crude.
Prices rose by about two percent on Friday after Iraq expressed its support for the production cuts implemented by the OPEC+ group, but they fell by nearly four percent during the week, recording losses for the third week in a row for the first time since May.
The US Energy Information Administration said last week that US crude production this year will increase slightly less than expected, while demand will decline.
Saudi Arabia and Russia, two major oil exporters, confirmed last week that they would continue voluntary oil production cuts until the end of the year, as concerns related to demand and economic growth continue to cast a shadow over crude markets.
The OPEC+ group, which includes the Organization of the Petroleum Exporting Countries (OPEC) and independent producers including Russia, will meet on November 26.