President Petro Poroshenko has warned Ukrainian politicians that the collapse of the Minsk agreements aimed at ending a war with Russia-backed separatists could set off a "full-scale conflict" with Russia.
Poroshenko was speaking at a conference of local leaders in Kyiv on January 23.
"Those political forces that want to torpedo the Minsk agreements at any cost...and to block the constitutional process, must clearly understand the consequences of their actions," he said.
"They will lead to the resumption of the 'hot phase' of the conflict, including a full-scale -- and not local, as it has been so far -- conflict with Russia," he added.
His words appeared to be aimed at foes of "decentralization" legislation that Ukraine is required to pass under the peace deal signed in February 2015 by Ukraine, Russia, and separatists who hold parts of the eastern Donetsk and Luhansk regions.
The Minsk deal is crucial for Kyiv because it calls for the restoration of Ukrainian control over the state border between the separatist-held territories and Russia, which has backed the separatists in a conflict that has killed more than 9,000 people since April 2014.
Ukraine's parliament gave preliminary approval to constitutional changes granting more power to the regions in August, but their adoption requires a two-thirds vote in the 450-seat legislature.
Poroshenko said he hopes the legislation will be passed in the first half of this year, in the next parliament session, which begins after February 1.
However, some lawmakers say the legislation must be passed during the current session to be valid, but that is highly unlikely to happen. As a result, Poroshenko's allies have asked the Constitutional Court for a ruling that would effectively extend the deadline for the vote indefinitely.
Poroshenko also said that adopting decentralization obviates any need to for laws granting "special status" to the separatist-held regions or any others, a remark that is not likely to please the separatists.