A Moscow court has acceded to a request from the Public Prosecutor to lay claim to 76 billion roubles (€2.1 billion) on bank accounts belonging to oil group Yukos.
A company statement today announcing the move said it "paralyses the productive capacity of Yukos" and prevented the company from settling accounts and paying its employees.
World crude prices rose today after the court's decision. New York light crude stood at $44.42 per barrel, 42 cents stronger on the day. London Brent gained 48 cents to $41.95 per barrel.
The threat of Russian supply disruptions, following hot on the heels of US inventory data showing a sharp draw on crude stockpiles, exacerbated fears for a tight market in the run up to the peak winter demand season.
Yukos , which pumps about 1.7 million barrels per day, or two per cent US of world supplies, has repeatedly warned it needs cash in its Russian bank accounts to fund core operations such as transportation fees to ensure oil exports.
Crude stocks in the US have fallen by 18 million barrels since early July as full-tilt refinery runs to meet peak summer gasoline demand take their toll on supply.
The sharp drop in inventories highlighted concerns for the adequacy of global supplies, at a time when demand is estimated to be growing at its fastest rate in 24 years.
"Despite the recent slide in prices, little has changed in the fundamentals of the oil market and the US weekly data should help to curtail speculative selling," wrote Barclays Capital analysts.
With the US summer driving season drawing to a close, analysts pointed to strong demand for distillate transport fuels.
"US distillate demand is growing at nearly seven US despite record diesel prices, indicating strong movements of inputs and finished goods around the U.S. economy," Barclays Capital said.
In Iraq, exports from the key southern terminals were back to near-full capacity following repairs to sabotaged pipelines.
Exports were running at 1.8 million barrels per day (bpd), shipping sources said.