The European Union has criticized Russia for pressuring Ukraine into abandoning a landmark free trade deal with the EU in favor of strengthening ties with Moscow.
EU leaders expressed frustration with Russia on Friday, the final day of a two-day EU summit in the Lithuanian capital, Vilnius.
EU President Herman van Rompuy said he hoped his bloc and Ukraine will sign the deal "sooner or later." He said there will be ongoing dialogue with Kyiv on the agreement to expand a free trade zone between the EU and Ukraine.
The summit was expected to mark the signing of the agreement.
But Ukrainian President Viktor Yanukovych refused to initial it. He told the summit Ukraine needs economic and financial support from the European Union before Kyiv can sign the trade deal.
Despite heavy pressure from Russia, two other former Soviet republics, Georgia and Moldova, initialed political and and trade agreements with the EU at the summit in Vilnius.
Last week, Mr. Yanukovych suspended any possible trade deal with the EU in favor of increasing ties with Russia.
That decision has sparked mass protests in Ukraine over the past week by pro-EU demonstrators urging Ukraine to enter into the agreement. The protests continued Friday in Kyiv, with demonstrators calling for Mr. Yanukovych to step down.
Russia has denied exerting political and economic pressure on Ukraine to delay the signing.
Last Sunday, tens of thousands of pro-Europe demonstrators gathered in one of the largest protests since the Orange Revolution nine years ago.