President Vladimir Putin said Thursday that Russia is "still open" to talks on Ukraine's gas debt, accusing the EU of failing to make specific proposals to help prevent a cutoff of supplies from next month.
In an open letter to European leaders, Putin also called on Brussels to "more actively engage" in finding ways to stabilise crisis-hit Ukraine's economy.
"Unfortunately, we have to say that we have not received any specific proposals from our partners as to how to stabilise the situation," Putin said in the letter released by the Kremlin.
He said Russia was "forced" to threaten to cut off gas supplies from June 3 after switching to up-front payments because Ukraine has amassed a gas debt of $3.5 billion (2.6 billion euros).
"The Russian Federation is still open to continue consultations and work together with European countries in order to normalise the situation," Putin said.
"We also hope that the European Commission will more actively engage in dialogue in order to work out specific and fair solutions that will help stabilise the Ukrainian economy."
Nearly 15% of all gas consumed in Europe is delivered from Russia via Ukraine and Brussels fears that a cutoff could lead to disruptions in supplies to the EU.
Ukraine has refused to cover its obligations in protest over Moscow's decision to nearly double the price it charges Kiev for gas imports following the February overthrow of its Kremlin-backed regime.
The danger for EU nations is that Ukraine -- its state coffers effectively empty and almost completely reliant on $17 billion promised by the International Monetary Fund -- will not cover its debt and instead start taking the gas Russia had earmarked for its European clients.
The nation of 46 million began dipping into supplies meant for Europe when it was cut off from Russian gas during previous price disputes in 2006 and 2009.
Putin pointed out that Russian gas giant Gazprom "has not received a single payment... despite the fact that Ukraine has received the first tranche of an IMF loan to the amount of $3.2 billion".
In Brussels on Tuesday, Ukrainian Prime Minister Arseniy Yatsenyuk said his government would take Russia to court unless it agreed to a gas supply contract based on market prices.