Oil prices dropped Tuesday on speculation that US crude inventories would have increased for a seventh week. Light, sweet crude for December delivery moved down 1.25 US dollars to settle at 93.37 dollars a barrel on the New York Mercantile Exchange, the lowest level in five months. Brent crude for December delivery lost 90 cents to close at 105.33 dollars a barrel. Oil prices are under pressure as U.S. crude stockpiles have increased in the past six weeks, mostly because of rising domestic production. U.S. crude supplies increased by 4.1 million barrels to 383.9 million barrels for the week ending Oct. 25 due to a strong increase in shale oil production. Traders expected a further increase of 2.5 million barrels for the week ending Nov. 1. The Energy Information Administration, the Energy Department's statistical arm, is due to release the weekly supply report on Wednesday. Investors are also closely watching major economic data due out this week to seek for clues to the Federal Reserve's future plan on its monetary policy. The Commerce Department will release the third-quarter gross domestic product figure on Thursday, followed by October's nonfarm payrolls report by the Labor Department on Friday. Analysts anticipated that the data may show the U.S. economy slowed in the third quarter. Last week, the U.S. central bank decided to keep easy monetary policy unchanged to bolster economic growth and job creation. Fed officials agreed to wait for more evidence that economic progress will be sustained before making any adjustment.