Oil prices hit a downward trajectory during the week ending Nov. 3 over demand constraints in the US and China, the world's largest and second biggest oil consumers, respectively.
International benchmark Brent crude traded at $86.75 per barrel at 1.43 p.m. local time (1043 GMT) on Friday, falling by around 4.12% relative to the closing price of $90.48 a barrel on Friday last week.
West Texas Intermediate (WTI), the American benchmark, was trading at $82.48 a barrel at the same time on Friday, down almost 3.57% from last Friday's session, which closed at $85.54 per barrel.
Oil prices fell after the American Petroleum Institute (API) and the Energy Information Administration (EIA) announced a buildup in the country's oil stockpiles.
The API estimated a rise in US crude oil stockpiles of 1.3 million barrels, against the market expectation of an increase of 1.6 million barrels. The EIA said inventory increased by around 800,000 barrels to 421.9 million barrels last week, signaling a decrease in oil demand in the world's largest oil consumer.
Concerns that China, the world's biggest oil importer, may see a downturn in oil consumption as a result of weaker-than-expected factory activity data also put downward pressure on oil prices this week.
Data showed a decline in China's manufacturing activity in October. The country's official manufacturing purchasing managers' index contracted to 49.5 last month.
Meanwhile, the US Federal Reserve's (Fed) decision to keep its federal funds rate unchanged pushed prices up midweek.
The Fed avoided an interest rate hike, as largely expected, to maintain its federal funds rate constant at between 5.25% and 5.5%, the highest level in 22 years.
Also, escalating tensions between Israel and Palestine continued to influence oil prices during the week.
The ongoing conflict between the two countries boosted fears that the clashes could escalate into regional turmoil, which could disrupt oil supply routes and deepen the supply deficit predicted for the rest of the year.
The Israeli army continues its advance on Palestine's Gaza Strip with no sign of a cease-fire.
By Zeynep Beyza Kilic