Russia is expecting Ukraine not just to pay $1.9 billion in advance for new gas but also to pay $2 billion that it owes for gas already supplied before gas deliveries can resume, Russian Energy Minister Alexander Novak told reporters.

Ukraine itself has said it intends to pay a first tranche of $1.5 billion towards its debt at the end of October.

"The $3.1 billion is what must be paid in two tranches: $2 billion before regular supplies begin and the remaining $1.1 billion before the end of the year. We differ firstly in that they are talking about three tranches - $1.5 billion, $0.8 billion and $0.8 billion; and secondly that this be paid after supplies begin," Novak said.

"This is the major point. The timing of the prepayment and settlement of part of the debt of $2 billion is a simultaneous process. It is fundamental for us that the portion of debt be paid before supplies begin. This is the position we aired in the spring, and that we are airing now. There can be no question of any supplies unless some of the debt is repaid. Otherwise we get a one-way street, where we again supply gas and the debt issue is just put off until later," Novak said.