It follows the expiry of a previous supply pact in July when Ukraine halted gas imports from Russia over a pricing dispute.
The head of Ukrainian state energy company Naftogaz, Andriy Kobolev, said it hoped to ink a renewed agreement in September that would likely run until the end of March 2016.
Ukraine had built up 14.7 billion cubic metres of gas in underground storage as of 7 September but needs to have between 18 and 19 Bcm in storage by mid-October.
The
