The Ukrainian government has launched talks on decentralising power as part of a European-backed peace plan, Reuters news agency reported.
Interim President Oleksander Turchynov opened the talks on Wednesday by saying Kiev was ready to listen to pro-Russian rebels in the east but would not bow to blackmail.
The meeting of political leaders government figures and regional officials did not include the pro-Russian separatists who have declared independence in two eastern regions. Without this inclusion, it was unclear what the negotiations might hope to accomplish.
The talks are part of the peace plan drafted by the Organisation for Security and Cooperation in Europe (OSCE), a trans-Atlantic security and rights group that includes Russia and the United States, but require the attendance of anti-Kiev groups under the proposal.
Interim Prime Minister Arseniy Yatsenyuk thanked the OSCE for its efforts but said Ukraine has its own plan to end the crisis.
In a speech in Brussels on Tuesday, he gave no details of that plan.
Opening the talks on Wednesday, Turchynov said, "Those with weapons in hand who are waging a war against their own country and dictating the will of a neighbouring country will answer before the law. We will not yield to blackmail."
"We are ready to listen to the people of the east but they must not shoot, loot or occupy government buildings."
Many separatists in the east shrugged off the round-table talks as meaningless.
"The government in Kiev does not want to listen to the people of Donetsk," said Denis Patkovski, a member of a pro-Russian armed group in Slovyansk, which has seen some of the most intense fighting in recent weeks.
"They just come here with their guns."
On Wednesday, Russian Foreign Minister Sergey Lavrov pushed for the separatists to be included in the round-table talks during an interview with Bloomberg television.
"We believe that for this national dialogue to succeed it is absolutely necessary to ensure equal participation of all regions of Ukraine," he said.
This included not only separatists in the east and south "but also the regions of the west where we also have some issues related to self-determination of minorities".
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Ukraine and the West have accused Moscow of fomenting the unrest in eastern Ukraine, where armed groups have seized administrative buildings, fought government forces and declared independence for the Donetsk and Luhansk regions after a self-rule vote last weekend that Ukraine and Western powers called a "sham".
The self-declared leaders of the regions also said that a planned May 25 presidential election would not happen in the "newly-independent states".
Lavrov on Wednesday said the worsening situation in Ukraine was another impediment to the upcoming election, AFP news agency reported.
"When Ukrainians kill Ukrainians I believe this is as close to a civil war as you can get," he said.
"And if this is conducive to free and fair elections then I don't recognise what free and fair is."
Ukrainian forces have mounted an offensive against the separatists, and dozens have died in the fighting across the east.