Prices had surged after the US Federal Reserve decided to continue with its $85 billion-a-month bond-buying programme to support US economic growth, confounding market expectations it will announce a scaling down of the scheme.

New York's main contract, West Texas Intermediate (WTI) for October delivery, fell 33 cents to $106.06 a barrel in morning trade after sinking $1.68 at the close in New York Thursday.

The European benchmark, Brent North Sea crude for delivery in November, dipped 15 cents to $108.61 after declining $1.84 in London the day before.

Research house Capital Economics said the US central bank's policy setting Federal Open Market Committee (FOMC) "looks as if it may now proceed even more cautiously than we had assumed".

"It seems likely that it will wait until its meeting in December at the earliest before announcing any tapering," it said in a note.

Other analysts said the return to production of Libyan oil fields and the easing of tensions in the Middle East after Syria agreed to a plan to put its chemical weapons arsenal under international control helped ease prices.