Russian gas giant Gazprom said Tuesday further Western sanctions against Russia could hurt its business and disrupt gas supplies to Europe.
The company and its staff have not been targeted by Western sanctions so far over Russia's role in the ongoing Ukraine crisis.
Gazprom CEO Alexei Miller has close ties to Russian President Vladimir Putin and could find himself in the West's sights, as harsher sanctions are threatened against Russia.
The gas company is embroiled in a dispute with the Kiev interim government over outstanding bills and the price it charges Kiev for gas. Gazprom has threatened to cut off supplies to Ukraine, which could also affect the flow of gas to Europe.
The EU relies on Russia for around a third of its gas needs, 40% of which reaches the bloc via Ukrainian pipelines.
"An expansion of the US, EU and other sanctions programmes could adversely impact operations and the financial condition of the Gazprom Group," the company said in a report after its 2013 financial results.
Gazprom almost doubled the price it charges Ukraine for gas this month and demanded immediate payment of $2.2bn worth of outstanding gas bills. The company recently announced it will seek a further $11bn from Ukraine's interim government, for fuel it promised to buy last year.
Kiev has refused to pay the new price which it labelled "political" and took initial steps on Monday to challenge the new pricing at an international court of arbitration.
Gazprom reported a 7% drop in net profit in 2013, in line with expectations. The company reported that revenue from gas sales to Europe and other countries reached 57% of total gas sales, worth 1.68tn roubles ($47bn, £28bn, €34bn).