"Going into the weekend with so much uncertainty in the air will only further fuel traders compulsion to get out of risky assets and it would take a miracle for the bulls to salvage anything today."
All sectors posted losses, with cyclical stocks like autos the major laggards.
The continued slide in oil prices dented sentiment ahead of third-quarter earnings season. Brent crude fell below $89 a barrel for the first time since 2010, before regaining some losses, while U.S.crude slid to its lowest since 2012.
Technip, a French engineering firm that works with energy companies, closed down just over 5 percent on Friday, taking an additional hit from a downgrade by Berenberg.
Heavyweights Shell, Total and BP all closed over 1 percent lower.
Remarks from European Central Bank (ECB) President Mario Draghi on Thursday also weighed. Speaking at the Brookings Institute, he reiterated that quantitative easing would not be effective without economic reforms, and warned of deflation risks.
In the U.S., stocks also fell on Friday, extending a rout that had the S&P 500 erasing its biggest rally in a year, with computer-chip manufacturers hard hit a day after Microchip Technology lowered its sales outlook.