Oil prices dropped for a second session Thursday, under pressure from an unexpected rise in U.S. crude stocks that raised concerns over demand after prices rallied to multi-year highs. U.S. crude slid 0.43%, or 33 cents, to $77.10 a barrel after the market climbed on Wednesday to $79.78, the highest since November 2014. Brent crude 2 cents, to $81.06 a barrel. U.S. crude inventories rose by 2.3 million barrels last week, the U.S. Energy Information Administraion (EIA) said, against expectations for a modest dip of 418,000 barrels. Gasoline inventories also rose, while distillate inventories were down slightly. U.S. crude inventories rose by 2.3 million barrels last week, the U.S. Energy Information Administraion (EIA) said, against expectations for a modest dip of 418,000 barrels. Gasoline inventories also rose, while distillate inventories were down slightly. The Organization of the Petroleum Exporting Countries and allies (OPEC+) said on Monday it would stick to its pact for a gradual increase in oil output, sending crude prices to multi-year highs.