European companies should start purchasing gas on Ukraine's border with Russia in order to guarantee that there are enough reserves at Ukrainian underground gas storage facilities (UGSF) by winter, Ukrainian Minister of Energy and the Coal Industry Yuriy Prodan said.

"We have invited European companies to buy gas from Gazprom at the Ukraine-Russia border. European companies have all the legal groundwork to purchase gas and store it at Ukrainian UGSFs. Of course the answer here rests with Gazprom, but we don't think Gazprom can refuse European companies in such a situation. And in any case, Ukrainian UGSFs will be provided with a reliable volume of gas," Prodan said at a briefing in Brussels on Wednesday.

European Union Energy Commissioner Gunther Oettinger has said that Europe would like to see reserves of around 20 billion cubic meters of gas at Ukrainian UGSFs by winter.

Current gas reserves at Ukrainian UGSFs total around 14.2 billion cubic meters.