Ukraine's prime minister says Russian President Vladimir Putin may be trying to restore the Soviet Union with the recent annexation of Crimea and pro-Russian unrest in eastern Ukraine.
Arseniy Yatsenyuk spoke on NBC television's "Meet the Press" Sunday, in a video link from Ukraine. He said restoration of the Soviet Union under Mr. Putin would be "the biggest disaster of this century."
Earlier, Russia said it is "outraged" by a deadly shootout in eastern Ukraine that breached an Easter truce. Ukrainian officials say details of the incident are not clear.
Officials say a shootout at a checkpoint manned by pro-Russian separatists has killed at least one person. Some reports say four people died, including separatists.
Russia said it is "outraged by this provocation by the fighters," and the attack proves there is a "lack of desire by the Kyiv authorities to rein in and disarm nationalists and extremists."
But a Ukrainian group blamed for the attack denies any involvement, and accuses Russian special forces for being behind the incident.
The assault happened near the town of Slavyansk, which is under the control of pro-Russian militants.
The attack came just hours after the Ukrainian government announced a pause in security operations to oust pro-Russian militants from buildings they have seized in recent days.
Foreign Minister Andrii Deshchytsia linked the suspension to the Easter holiday, and said the pause would give European monitors more time to organize a special mission aimed at de-escalating tensions in eastern Ukraine.
A VOA correspondent in Kyiv said the diplomat's comments came after concluding a meeting with the Organization for Security and Cooperation in Europe and ambassadors from Russia, the United States and the European Union.
Pro-Russian gunmen have seized Ukrainian government buildings in nearly a dozen eastern cities and say they will not surrender until the interim Ukraine government in Kyiv steps down.
In Moscow Saturday, Kremlin spokesman Dmitry Peskov admitted that Russia had deployed additional security forces to the Ukrainian border in response to the instability in Ukraine. Russia has previously said its troops were on the border for routine exercises.
U.S. President Barack Obama has warned Russia that it could face additional sanctions if it fails to adhere to a new international deal on Ukraine reached Thursday in Geneva. That agreement, which followed talks between Ukraine, Russia, the United States and the European Union, calls for all government buildings to be evacuated and for the militants to be disarmed. But it includes few concrete measures for ending the crisis, and many Western leaders are skeptical about Russia holding up its end of the bargain.