Oil prices fell below $87 a barrel on Tuesday in Asia, snapping a week of gains that were fuelled by investor optimism the global economy may not slow as much as feared in the second half. Benchmark oil for September delivery was down 99 cents to $86.89 a barrel at late afternoon Singapore time in electronic trading on the New York Mercantile Exchange. Crude surged $2.50 to settle at $87.88 on Thursday. In London, Brent crude for October delivery was down $1.21 to $108.70 per barrel on the ICE Futures exchange. Oil fell below $76 on August 9 on investor fear the US could be headed for a recession, which would drag down demand for crude. However, later that day the US Federal Reserve pledged to keep its lending rates low for the next two years.