Oil prices tumbled to a three-month low on Thursday as dealers turned their attention to swelling U.S. crude inventories and signs of slower global demand growth. U.S. crude futures dropped $1.91, or 3.8 percent, to $48.54 a barrel, adding to a $1.62 decline Wednesday triggered by a U.S. government report showing stockpiles at their highest since July 1999. "The market is still digesting bearish inventory numbers for crude," said Jason Schenker, an economist at Wachovia Corp. in Charlotte, North Carolina. Oil prices have fallen around 17 percent from their peak of $58.28 struck in early April as runaway production from OPEC-member nations translates into a flood of crude shipments to U.S. shores. Oil inventories in the United States, the world's largest energy consumer, have climbed 9 percent so far this year and are 10 percent above their levels a year ago. Qatari Energy Minister Abdullah al-Attiyah said on Thursday, in a statement carreid by Reuters that it was too early for OPEC to decide to rein in its production, despite the drop below $50 a barrel. --More 2219 Local Time 1919 GMT