"Unfortunately, and I would like to underline this, all the efforts have so far yielded no results," Medvedev said. "And people who live in many European countries still remain without heat."
The Russian leader said Moscow was ready to do "everything it could" to resolve the gas crisis.
Russia's state-run gas giant Gazprom said on Saturday it expected to sign a deal with Ukraine resolving the dispute which has interrupted supplies of Russian gas to Europe, Russian news agencies reported.
"We expect that today documents will be signed," Interfax news agency quoted Gazprom spokesman Sergei Kupriyanov as saying on the sidelines of a Kremlin meeting of gas consumers. "The main thing now is to resolve the transit question."
A Ukrainian delegation headed by Prime Ministry Yulia Tymoshenko was in Moscow on Saturday for talks with Russian Prime Minister Vladimir Putin.