Russian Foreign Minister Sergei Lavrov says that Ukrainian legislation on the status of rebel-held eastern regions is a "glaring violation" of a European-brokered peace deal signed last month in Minsk.
Ukraine's Verkhovna Rada approved legislation on March 17 setting the boundaries of territory to be granted "special status" entailing a measure of autonomy but stipulated that it should come into force only after elections are held under Ukrainian law.
Russia and the rebels claim that violates the terms of the Minsk agreement, with separatist leaders in eastern Ukraine threatening on March 18 to abandon the cease-fire.
In comments on March 18, Lavrov lashed out at Kyiv over the amended legislation, suggesting it would badly undermine the chances of reaching a politcal settlement between Ukraine and Russian-backed separatists.
"What comes out of parliament's decree is that only when these territories are led by somebody suitable for Kyiv will the law on special status come into effect," he said. "That is an attempt to turn everything that was agreed upon on its head."
"I don't know how the political process will go now," Lavrov added.
He said he had sent a message to the foreign ministers of Germany and France that "drew their attention to the glaring violation of the first steps of the political part of the Minsk package."
Separatist leaders in eastern Ukraine's Donetsk and Luhansk regions also sharply criticized the legislation, accusing Kyiv of "trampling" the deal reached on February 12 at talks between Ukrainian President Petro Poroshenko, Russian President Vladimir Putin, German Chancellor Angela Merkel, and French President Francois Hollande.
"We agreed to a special status...within a renewed Ukraine, although our people wanted total independence," separatist leaders Aleksandr Zakharchenko and Igor Plotnitsky said in a statement. "We agreed to this to avoid the spilling of fraternal blood."
They said, "Poroshenko and [Ukrainian Prime Minister Arseniy] Yatsenyuk have cynically mocked their EU sponsors who took a great negotiating effort."
"Kyiv does not need peace. It seeks to destroy Donbas by violence and economic siege," the statement added.
A Ukrainian Foreign Ministry spokesman said in an e-mailed statement to the Associated Press on March 18 that enacting the special status law without elections approved by Kyiv would amount to legitimizing what Ukraine considers unlawful rebel governments.
Granting "special status" is part of a series of measures agreed to in the February 12 deal, which also established a cease-fire starting on February 15 and called for the withdrawal of heavy weapons far behind front lines in the conflict, which has killed more than 6,000 people since April 2014.
Fighting has decreased sharply under the cease-fire but persists, with each side accusing the other of violations and Kyiv expressing concern the separatists may be using the truce to regroup for possible further offensives.
Ukrainian military spokesman Andriy Lysenko said on March 18 that one serviceman was killed and five were wounded in rebel attacks over the previous 24 hours.
"The enemy continues to strengthen covertly its groups near the separation line between opposing forces," Lysenko said in a televised briefing.
The angry reaction from Russia and the rebels clouds the chances for further implementation of the peace deal, which calls for the withdrawal of foreign forces and for restoration of Ukrainian control over its border with rebel-held territory by the end of 2015 if certain conditions are met.
On March 17, the Ukrainian legislature also declared the rebel-held areas temporarily occupied territories.
Moscow denies sending troops and weapons into eastern Ukraine despite what Kyiv and NATO say is incontrovertible evidence of direct Russian military support for the rebels.
With reporting by AP, Reuters, RIA Novosti, and TASS