Oil giant BP has closed down its largest oilfield in the US, Alaska's Prudhoe Bay, following a pipeline leak.
Yesterday's closure of oilfield, which produces about eight per cent of US daily oil output, saw the price of crude rise further, amid ongoing concern about supplies given the current conflict in Lebanon.
The announcement of the indefinite shut down of the Alaskan oil field led prices to rise by almost two per cent to $76 a barrel.
The closure of the field, which produces some 400,000 barrels a day, comes as BP already faces a criminal investigation over a bigger leak at the site in March.
The company said that it had taken the decision to close the oil field after finding "unexpectedly severe corrosion" to a pipeline.
"We do not know how long the field will be down but we will not resume operation of the field until we and government regulators are satisfied that they can be operated safely and pose no threat to the environment," said BP spokesman Darren Beaudo.
Although BP has never previously closed down Prudhoe Bay, it has been forced to curb production at the oil field several times over the past year due to a series of incidents and spills on the oil-rich North Slope.
The latest leak will place BP's US operations under further scrutiny.
In addition to the criminal probe over the previous leak at the plant, the company is also under investigation following a fatal explosion at its Texas City refinery in March.
Authorities have also accused BP of trying to manipulate US energy prices by withholding large amounts of propane from the market in February 2004.