Naftogaz Ukrainy will not, in keeping with a ruling by the Arbitration Institute of the Stockholm Chamber of Commerce on Friday, be paying for gas that Russia's Gazprom has supplied to parts of the Donbas that are not controlled by Kyiv.

"Naftogaz is not responsible for alleged gas deliveries to the uncontrolled territories in the east of Ukraine," the company said in a press release.

"The Stockholm Tribunal stated that gas delivered to someone else than Naftogaz in the occupied territories of the Donetsk and Luhansk regions should not be the responsibility for Naftogaz to pay for. Also future deliveries to these territories are not the concern of Naftogaz as long as the occupation remains. Any such deliveries will not be accounted for in the annual contract volume," it said.

"Basically, whoever supplied the gas to ORDLO [the Ukrainian acronym for the Donbas territory not in its control] can pay for it," Naftogaz said in facebook.

Naftogaz Chief Commercial Officer Yuriy Vitrenko told journalists in Kyiv on Wednesday that Gazprom is currently claiming payment of $1.3 billion for supplies to that territory.