“On March 21st Gazprom filed a request to the Court of Appeals in the Svea District to partially annul the final arbitration ruling with Naftogaz Ukraine on the subject of deliveries” of gas, the firm said in a statement on Thursday.

It said the appeal was motivated by errors of procedure and abuses committed by the arbitrators.

Last month the Stockholm Arbitration Court ordered Gazprom to pay $2.56 billion to Naftogaz to settle all of their legal disputes and ordered the resumption of deliveries of Russian gas to Ukraine.

The two companies had demanded tens of billions of dollars from each other in a dispute over an expensive 10-year contract Ukraine signed in 2009 after Gazprom cut its deliveries in the middle of the winter.

Gazprom refused to restart deliveries as ordered at the beginning of March and had indicated it planned to appeal the ruling.

Moscow and Kiev have had a number of disputes over gas supplies in recent years, some of which led to reductions in supplies to other European countries via pipelines that transit Ukraine.

Roughly 15 percent of the gas Europe buys from Russia is transported through Ukraine.