Ukrainian President Petro Poroshenko says he will submit a bill to parliament next week to grant "special status" to areas in eastern Ukraine but that the country will remain united.
Poroshenko told a televised government meeting on September 10 that a peace accord signed with pro-Russian separatists on September 5 preserves the concept of Ukraine as a sovereign, united country within its current borders.
"We will not make any concessions to anybody on the issue of the sovereign structure of our state, the issue of independence, and the issue of territorial integrity. We remain a united state," he said.
The separatists have said that despite the accord signed in Minsk, which called for decentralization of power and an "inclusive national dialogue," they still intend to break away from Kyiv.
Poroshenko said that the Minsk protocol "prescribes the restoration and preservation of Ukraine's sovereignty in the whole Donbass region, including the territory which is temporarily under rebel control."
He said that "there is no -- and there could not be -- federalization and forfeiture of this territory."
Poroshenko also said a cease-fire between government forces and pro-Russian separatists who hold parts of the eastern Donetsk and Luhansk regions has been difficult to maintain, saying "the terrorists are trying all the time to provoke" their opponents.
But he said, "The situation has radically changed at the front" since the cease-fire came into effect on September 5.
Russian President Vladimir Putin's foreign policy adviser, Yury Ushakov, said that Putin and Poroshenko, in a telephone conversation on September 9, broadly agreed that "the cease-fire is being observed although it is a difficult process."
Poroshenko said government forces were regrouping in eastern Ukraine to reinforce defense, not for a new offensive.
He said he did not rule out introducing a "special regime" in areas adjacent to the conflict zone.
Russian Foreign Minister Sergei Lavrov on September 9 claimed there was a heavy concentration of government forces in an area northeast of Donetsk and accused Kyiv or preparing a strike against the rebels despite the cease-fire.
Poroshenko also said Russia has withdrawn 70 percent of the troops Kyiv claims had been in eastern Ukraine back across the border.
He did not give numbers, but NATO has said there were several thousand Russian soldiers in Ukraine.
Russia denies sending any troops into eastern Ukraine in support of the separatists, despite what the Ukrainian government and the West say is overwhelming evidence to the contrary. Moscow also denies arming the separatists.
Also on September 10, Poroshenko signed a law allowing the government to impose sanctions on Russian companies and individuals suspected of supporting and financing separatist rebels in eastern Ukraine.
The law was passed by parliament last month.
It allows for more than 20 types of sanctions including travel bans and asset freezes, restrictions on trade, the transit of resources and transportation of goods across Ukraine.
The legislation provides the legal basis for the sanctions, but does not impose them. Specific sanctions will have to be approved by the National Security and Defense Council.
The government has drawn up a list of 172 citizens of Russia and other countries, and of 65 Russian companies, which could be targeted by sanctions. The list has not been made public.
With reporting by Reuters and Interfax