National joint-stock company Naftogaz Ukrainy CEO Andriy Kobolev has said that Russia's Gazprom could refuse signing a long term contract for gas transit via Ukraine's gas transmission system (GTS) with the start of operations on general terms through reserving capacities for some period of time.

"Gazprom, in general, could decide not to sign a contract with Ukraine. At the end of 2019, Gazprom could come to the operator of the GTS, which is to be prepared for unbundling with Naftogaz Group, and simply order the services, as other shippers do now," he said on Channel 5 TV late on Wednesday.

"This will mean that Gazprom will pay the same tariff, which is paid by the rest [of the shippers] on general terms. It could reserve the amount of gas for transit, for example for 2020, or for six months, or for one month, using this mechanism," he said.

Kobolev reiterated that Gazprom is delaying the talks with Naftogaz on the signing of the transit contract due to the political instruction to wait until the end of the presidential election in the country.

As reported, the capacity of Ukraine's gas transport system is 288 billion cubic meters (bcm) at the entrance and 178.5 bcm at the exit, of which 142.5 bcm goes to European countries and 3.5 bcm goes to Moldova.