KIEV, July 29 /ITAR-TASS/. Ukraine’s national energy company Naftogaz has proposed to review a gas transit contract with Gazprom, the Ukrainian news agency UNN reported on Tuesday, citing Naftogaz head Andrei Kobolev.

The contract signed in 2009 stipulates the terms of Russian natural gas supplies to Europe via Ukraine through 2019.

“We have sent a letter to Gazprom with a demand to review the transit contract,” Kobolev said. “This process has been initiated.” Kobolev declined to disclose details of Ukraine’s proposals on the contract review.

Kobolev said the proposals related to changes in the methodology of registering gas volumes.

The Naftogaz head earlier said the Ukrainian energy company could apply to the Stockholm Arbitration Tribunal, if Gazprom refused to hold negotiations on reviewing the gas transit contract.

Gazprom halted gas supplies to Ukraine from June 16 over the ex-Soviet republic’s enormous gas debt to Russia while continuing pumping natural gas to Europe via Ukraine.