Ukrainian Energy Minister Yuri Prodan is scheduled to meet European Energy Commissioner Guenther Oettinger on Thursday in an attempt to work out a date and venue for the next round of talks with Russia aimed at resolving a gas crisis.
The European Union's executive hopes to broker a deal to resolve a stand-off in which Moscow has shut off gas deliveries to Ukraine since mid-June over what it says are more than $5 billion in unpaid bills.
The trilateral talks had been expected later this week after progress was made at a meeting in Brussels last Friday.
However, differences remain over Ukraine's debt for already delivered gas as well as the price it is willing to pay for any future supply.
Russia's Energy Ministry said on Wednesday that the talks have been postponed and the new date for the meeting would be decided next week.
Ahead of that, Prodan and Oettinger will meet on Thursday in Brussels, a European Commission source said.
"The bilateral meeting aims at preparing the next trilateral gas talks for which a date and place have not been scheduled yet," the source said.
Russia halted gas flows to Ukraine on June 16 citing Kiev's debt for gas supplies, which Moscow puts at $5.3 billion. Ukraine disagrees with the amount due to differences over the price.
Prodan will also attend a roundtable in Brussels to discuss possibilities of investment into Ukrainian gas pipeline system, which has long been eyed by Moscow and seen as a strategic asset by Kiev.