News agency Interfax cited diplomatic sources in its report, issued amid high tension over Putin's move to make Ukraine's Crimea region part of Russia.

"No. President Van Rompuy will not go to Moscow tomorrow," Preben Aamann, a spokesman for Van Rompuy, said on Tuesday. "He will be preparing for the European Council in Brussels on Thursday/Friday this week."

After Crimeans voted to join Russia in a weekend referendum dismissed by the EU and United States as a violation of Ukraine's sovereignty, Putin signed a treaty with Russian-backed Crimean leaders on Tuesday to bring the region into Russia.

"The European Union does not and will not recognise the annexation of Crimea and Sevastopol to the Russian Federation," Van Rompuy and European Commission President Jose Manuel Barroso said in a joint statement on Tuesday.

They said the European Council would discuss Ukraine at its meeting this week and "agree on a united European response."

The EU and United States have imposed visa bans and asset freezes on several Russian officials and lawmakers.