Russian oil major Yukos yesterday suspended most of its oil exports by rail to China in the first sign of supply disruptions due to its financial difficulties, which could push world prices higher.

A Yukos spokesman said the board had decided last week to suspend deliveries to the China National Petroleum Company, representing some 400,000 tonnes per month, or 100,000 barrels per day.

"But supplies to Sinopec, representing about 200,000 tonnes per month, are continuing so far," the spokesman said, referring to Asia's largest oil refiner.

The spokesman said the cut was due to "problems we are facing in paying our export duties and railway fees because our bank accounts are frozen".

Yukos is Russia's largest exporter, sending around a million barrels a day to Western markets and China. It has often said it may be forced to cut production and exports after bailiffs froze its bank accounts as part of efforts to recover more than $7 billion (€5.7 billion) in back taxes.