Ukraine may transfer prepayment to Russia for the supply of the amount of gas Ukraine needs, Ukrainian Energy and Coal Industry Minister Yuriy Prodan told reporters in Kyiv on Tuesday.

"Gas purchase plans haven't changed: we plan to buy up to 1.5 billion cubic meters of gas by the end of the year. The purchases will start with the cold weather. Most likely we'll start before December 1. The situation isn't critical at the moment," he said.

Prodan, however, declined to disclose the size of the prepayment.

The agreement between NJSC Naftogaz Ukrainy and Russia's gas giant Gazprom allows Kyiv to purchase as much natural gas as it needs depending on the current situation, the minister added.

Prodan said late last week that Naftogaz planned to buy up to 1.5 billion cubic meters of natural gas from Gazprom before the end of the year, and another 1 billion cubic meters in the first quarter of 2015.

Ukrainian Prime Minister Arseniy Yatseniuk said earlier that Ukraine may need 5 billion cubic meters of gas for the upcoming heating season. However, it was said at one of the final rounds of Ukraine-Russia-EU talks that Ukraine may buy up to 4 billion cubic meters of gas before the end of 2014.

Under the Brussels agreements, Ukraine will pay $378 per 1,000 cubic meters of Russian natural gas until the end of 2014, and $368 per 1,000 cubic meters in January-March 2015.

Repayment by Ukraine of its $1.65 billion debt for previous supplies by the end of 2014 will make it possible for the country to buy new gas from Russia.