Russian President Vladimir Putin says Russia is ready to reduce by $100 the price Kyiv pays per 1,000 cubic meters of Russian natural gas -- from $485 to $385.
Putin and Russia's energy minister, Aleksandr Novak, said on June 11 that the government was also ready to guarantee the discounts will remain in place for one year, to assuage Kyiv's fears.
Putin said the offer was made in a "partnership" spirit, and warned that if Kyiv turns it down, "we will move to quite another stage."
But Ukrainian Energy Minister Yuriy Prodan said Kyiv was not accepting the offer and was ready to take the issue to the Stockholm International Arbitration Court.
Ukraine is willing to pay $268 per 1,000 cubic meters.
Prodan spoke in Brussels after gas talks with Russia mediated by the European Union.
EU Energy Commissioner Guenther Oettinger said the two sides will continue to try and make progress in the next 48 hours.
Russia has set a June 16 deadline for Ukraine to pay its outstanding gas debt that Moscow estimates to be $2.8 billion, with an additional $1 billion due on June 26.
A Ukrainian source did, however, tell RFE/RL that Moscow is unlikely to stop gas deliveries as long as negotiations are ongoing.
Ukrainian Prime Minister Arseniy Yatsenyuk on June 11 dismissed Moscow's offer as a "Russian trap."
"If gas is a commodity, as it is all over the world," Yatsenyuk said, "then we are trading on the basis of the contract and not on the basis of whether Russia likes or dislikes the Ukrainian government."
Russia more than doubled Ukraine's gas price -- from $268 to $485 per 1,000 cubic meters -- after pro-Russian President Viktor Yanukovych was ousted in February.
With reporting by Reuters, AP, and Interfax