LONDON: World oil prices fell Thursday as traders took profits from the previous day's gains and fretted over the outlook for weak demand, analysts said.

New York's main contract, light sweet crude for delivery in December sank 45 cents to 79.95 dollars a barrel.

Brent North Sea crude for December delivery shed 50 cents to 78.39 dollars in London trade.

The US Federal Reserve on Wednesday held rock-bottom interest rates for "an extended period" and kept trillion-dollar stimulus measures in place to support a fragile recovery from recession.

As expected, the Fed held its key federal funds rate at a historic low of zero to 0.25 percent, where it has been since last December to help pull the economy out of the worst downturn since the Great Depression.

The US central bank added that "although economic activity is likely to remain weak for a time," its policy actions would support the recovery.

"The Fed is not pointing at any strong demand recovery and the US oil statistics are saying the same thing," said Petromatrix oil market analyst Olivier Jakob.

"US demand for petroleum products has been very stable for the last five month and while stability is better than continued erosion it is not yet showing any sign of rebound," he warned.

Prices eased Thursday after briefly breaching the 81-dollar mark in New York on Wednesday, reflecting concerns over demand, analysts said.

"The fundamentals of the markets are still weak... and there are no signs of steadily growing demand," said Jason Feer, Asia-Pacific vice-president of energy market analysts Argus Media in Singapore.

He added that data released by the US Department of Energy (DoE) on Wednesday showing an unexpected dip in US crude reserves was "overall not that much" in the larger scheme of prices.

The DoE announced that crude reserves in the world's largest energy consumer sank by four million barrels in the week ending October 30, surprising analysts, who were expecting a rise.

Oil prices have climbed in recent months amid a commodities rally that has seen gold futures strike a series of record highs.

The price of gold surged to an all-time peak on Wednesday in the wake of the International Monetary Fund's massive sale of the precious metal to India.

Gold and other commodity prices have climbed in recent months amid a move away from the dollar, which has been slumping. The move accelerated last month on a report that Gulf states may stop using the greenback for oil trading.