MOSCOW, August 29. /ITAR-TASS/. Cases of Ukraine’s unsanctioned siphoning of Russian natural gas intended for European countries and supplied via the territory of Ukraine are possible ahead of the heating season, Russian Energy Minister Alexander Novak said on Friday.

“The situation is highly critical ahead of the heating season,” Novak told journalists following his meeting in Moscow on Friday with EU Energy Commissioner Gunther Oettinger.

Oettinger arrived in Moscow on Friday for gas talks with Russia. The commissioner was scheduled to hold talks with Russian Energy Minister Novak and Gazprom CEO Alexei Miller to try to find a solution to the Russia-Ukraine gas price dispute.

The commissioner’s spokesperson, Marlene Holzner, earlier said that Oettinger would present the European Commission’s new proposals on a gas compromise between Russia and Ukraine as part of preparations for resuming ministerial gas talks between Moscow, Kiev and EU officials.

Holzner also said on Thursday that disruptions in supplies of Russia’s natural gas across the territory of embattled Ukraine to the European Union's member states were possible this coming winter.

She said inquiries were sent to all European Union member states to find out how they would cope with shortage of the Russian natural gas during the winter period in case Ukraine halts the transit of the gas across its territory.

She added that the European Commission expects the EU member states to deliver reports in October on the state of their natural gas reserves.

Ukrainian Prime Minister Arseniy Yatsenyuk earlier said his country was likely to halt transit of the Russian natural gas to Europe this winter.

Gazprom says Naftogaz’s debt under the “take or pay” clause has already exceeded $11 billion.

Gazprom halted gas supplies to Ukraine in June over its unpaid debt and filed a $4.5 billion suit to the Stockholm arbitration court. Later, Kiev reciprocated by sending a suit to the court against Gazprom for making Ukraine overpay $6 billion for gas since 2010, setting too high prices in its contract.

Miller also said that Gazprom had not received any signal from Naftogaz about the Ukrainian company’s readiness to repay debts for natural gas supplied to Ukraine in previous months. Gazprom says this debt has already topped $5 billion.

Brussels and Kiev have elaborated a joint position that gas prices for Ukraine should be at the level of $320 per 1,000 cubic meters during the summer season until mid-October and $385 per 1,000 cu m during the heating season. Ukraine however, earlier rejected a seasonal scheme proposed by Gazprom.

At a meeting held in Minsk on Tuesday between the leaders of Russia, Belarus and Kazakhstan, which form the Customs Union, EU officials and the Ukrainian president, Russian Energy Minister Novak said that Russia’s position was unchanged and Ukraine must repay its $5 billion debt to continue cooperation with Moscow.