Ukrainian President Petro Poroshenko has said there must be political liability for the signing of gas contracts with Russia in 2009.

"I am saying that there must be responsibility [taken for this]. I am not speaking about criminal responsibility – that is not for the president to decide. We have the necessary [law-enforcement] agencies. I am speaking about political responsibility for putting the country on its knees. Today this has been proven, not by politicians, not by domestic experts, but by the highest international legal institution. It has been proven that the interests of Ukraine were compromised," Poroshenko said during a visit to the Trypilska combined heat and power plant (CHPP) on Thursday.

The head of state spoke of the recent decision of the Stockholm Arbitration court, which refused to recognize the "take or pay" principle incorporated in the gas contract.

"The predatory take-or-pay principle means that, no matter how much gas you consume, you'll pay for 52 billion cubic meters, even though we have never consumed that much. And there was a criminal signature given, and absolutely unlawful, non-market, and corrupt obligations were undertaken," he said.

It had been reported earlier that the Petro Poroshenko Bloc faction at the Ukrainian Verkhovna Rada had urged anti-corruption bodies to scrutinize the details of the Ukrainian-Russian gas delivery contract concluded in 2009 by then Prime Minister Yulia Tymoshenko.

Speaking at a meeting of the conciliatory council of the heads of the parliamentary factions, committees, and groups on Tuesday, Artur Herasymov, the head of the Petro Poroshenko Bloc parliamentary faction, called on the Rada's national security and defense committee and anti-corruption committee to summon Tymoshenko to their sessions and look into "high treason and a corruption element in the 2009 gas contract."

During Viktor Yanukovych's presidency, Tymoshenko was convicted of abuse of office in concluding the 2009 gas contract with Russia.