President Vladimir Putin has warned German Chancellor Angela Merkel of a threat to the gas supplies that Russia sends to Europe via Ukraine, the Kremlin said on December 13.
Putin told Merkel in a telephone call that Ukraine has been reluctant to sign a contract on Russian gas supplies for the coming winter and that it "threatens transit to Europe."
Moscow has warned that Ukraine could siphon off Russian gas intended for European consumers.
A spokesman for the Ukrainian prime minister said, however, that Ukraine remains a reliable transporter of Russian gas to European consumers.
"Natural gas delivered by Gazprom to the eastern border of Ukraine for transport purposes will be shipped to the western border in a proper way, in full amount, and in keeping with the existing contract for natural gas transportation concluded between Naftogaz of Ukraine and Gazprom," Dmytro Stolyarchuk told the Interfax news agency.
European nations receive about a third of their gas imports through a pipeline that transits Ukraine. Past disputes between Moscow and Kyiv have led to cutoffs, including a 2009 standoff that caused serious disruptions in winter supplies.
A new dispute surfaced during negotiations over gas delivery on December 9, with Kyiv demanding new contract terms that Moscow refuses to provide.