The Kremlin says Moscow and Kyiv have not signed an agreement on reducing Russian gas prices, and did not discuss Ukraine’s possible membership of a customs union at a meeting on Friday.
The two countries’ presidents met on Friday in Russia’s Black Sea resort of Sochi.
Dmitry Peskov, a spokesman for the Russian president, said Vladimir Putin and Ukrainian President Viktor Yanukovych discussed “cooperation in energy”, but that “no final agreement” had been reached.
Arseniy Yatsenyuk, a Ukrainian opposition leader allied to the jailed former prime minister Yulia Tymoshenko, had warned that an accord with Russia would be a “political and economic catastrophe”.
Tension has been reported on Saturday around the state TV headquarters in Kyiv, amid anti-government protests that began when a planned deal with the EU was called off.
Special police forces are said to have taken over the signal tower, they say to ensure security because of protests nearby..