Oil prices have fallen below $90 a barrel on worries that the spreading financial crisis will exacerbate a global economic slowdown and cut demand for crude oil.

Light, sweet crude for November delivery was down $4.69 to $89.19 a barrel in electronic trading on the New York Mercantile Exchange by late afternoon in Singapore.

Oil prices have tumbled nearly 40 percent since peaking in July.

The drop came as world stock markets plunged amid growing investor anxiety of a global financial crisis triggered by the bad debt mess in the U.S.

Oil demand in the world's richest countries had already begun to slow since May, before the worst of the financial turmoil erupted last month.