EU leaders meet later on March 6 to debate whether to impose sanctions on Moscow for sending troops into Ukraine's Crimea region.
The European Union on March 5 decided to freeze the assets of 18 Ukrainian citizens responsible for the misappropriation of Ukrainian state funds.
Brussels has not yet confirmed the identities of the individuals, but EU sources tell RFE/RL that former Ukrainian President Viktor Yanukovych and his closest advisers are included on the list.
The emergency summit in Brussels comes a day after little progress was reported in talks in Paris involving ministers from Ukraine, Russia, Britain and France.
U.S. Secretary of State John Kerry described his March 5 meeting in Paris with Russian Foreign Minister Sergei Lavrov as "tough" and said the two would meet again on March 6 in Rome.
"We agreed to continue intense discussions in the coming days with Russia, with the Ukrainians in order to see how we can help normalize the situation, stabilize it and overcome the crisis, and those intentions are intentions that are shared exactly as I have described them between Russia, the United States, the European countries and Ukrainians who were here. All parties agreed today that it was important to try to resolve these issues through dialogue," Kerry told reporters.
In Paris, Lavrov refused to meet his Ukrainian counterpart. The Kremlin insists the new authorities in Kyiv are not legitimate.
Talks in Paris came amid ongoing tensions in Ukraine's Crimea, where pro-Russian forces are locked in a tense standoff with the Ukrainian military.
Lavrov repeated Moscow's claims that the troops that have seized control of much of the Black Sea peninsula are not under Russian command, but rather local "self-defense" forces, a claim largely ridiculed in the West.
A UN envoy, Robert Serry, was forced to leave Crimea on March 5 after being confronted by an angry pro-Russian mob.
Serry has since flown to Istanbul.
In the eastern Ukrainian city of Donetsk, pro-Russian protesters retook control of the regional administration building.
NATO, meanwhile, announced it was reviewing its cooperation with Russia and boosting ties with Ukraine's new leadership.
U.S. Defense Secretary Chuck Hagel said Washington will more than double the number of U.S. fighter jets on a NATO air patrol mission in the Baltics and give more support to Poland in a bid to reassure allies alarmed by the crisis in Ukraine.
Based on AP and Reuters reporting