Ukraine on Wednesday said gas was still flowing to Europe despite a supply cut from Russia and invited the EU to send inspectors to ensure stocks were not being siphoned away.
Europe gets about 30 percent of its gas from Russia, with half of that transiting through Ukraine, but on June 16 Moscow cut off supplies intended for Kiev amid a bitter price dispute.
"We do not have any problems with gas supplies to Europe," Ukrainian Energy Minister Yuriy Prodan said after talks with EU Energy Commissioner Guenther Oettinger.
"Ukraine demonstrated it can deliver gas to European countries (despite the gas cut)," he added.
Russia already cut supplies in 2006 and 2009, causing havoc in Europe during the winter, and said last week it would deliver no more gas intended for Ukraine unless Kiev paid a set price upfront.
To preempt accusations that Ukraine was tapping into gas flows meant for Europe, Prodan asked the EU to send inspectors to oversee reserves.
Oettinger said the proposal "was constructive and we can do it within the next day or weeks."
Ukraine and Russia are already locked in a deadly confrontation after the annexation of Crimea and several rounds of EU-brokered gas talks have failed.
Moscow insists that Kiev pay $1.95-billion (1.45-billion-euro) gas debt immediately and accept a price of $385 per for 1,000 cubic metres of gas that Kiev says is too high.
The EU and Ukraine confirmed they exploring alternative gas sources for Ukraine, especially the expansion of so-called "reverse flows", sending gas already in Europe back east to Ukraine.
"We share the common outlook to avoid disruptions in the EU market and Ukraine this winter," Oettinger said.