BP shuts biggest US oil field

Oil producer BP Plc began shutting down on Sunday the biggest oilfield in the United States, Alaska's Prudhoe Bay, after discovering a small pipeline leak, cutting output by 400,000 barrels daily and sending oil prices up nearly 2 percent.

BP, already part of a criminal probe into a much bigger Alaskan pipeline rupture in March, was unable to estimate when output might resume at the field, which accounts for about 8 percent of U.S. domestic crude oil production.