Ukraine told the UN Security Council that its cease-fire with separatists in the east must be strengthened before progress can be achieved on a political solution to the two-year conflict.
Ukrainian Deputy Foreign Minister Vadym Prystaiko suggested the Orthodox Easter holiday this weekend might provide an opportunity to shore up the truce after a surge of violations in recent months.
"If we can start with that, we can then proceed to withdrawal of forces and resolving of all the problems -- demining, humanitarian problems -- all the way down to a political resolution," he told the council on April 28.
It was the first Security Council meeting on Ukraine since December. Ukraine requested the meeting to discuss cease-fire violations in the eastern Donetsk region that OSCE monitors say have reached worrying levels over the past few weeks.
Ukraine detailed accusations that Russia is providing military backing for the separatists, a claim Moscow rejects.
"Russia has organized and deployed in Donbas a 34,000-strong hybrid military force consisting of regular Russian troops as well as of foreign and local militants," Prystaiko said.
"Russian generals and military officers provide direct command-and-control of this illegal military entity [which is] impressively heavily armed," he said.
Prystaiko dismissed Russian claims that the separatists' arms were purchased in local hardware stores.
"Last time I checked, you will hardly be able to buy a decent knife in Ukrainian hardware stores, not to mention the multiple-launch rocket systems and jet flamethrowers," he said.
The United States, France, and Britain back Ukraine's assertions and have blamed Russian aggression for starting the conflict.
"What is happening today is the result of Russia's violation of Ukraine's sovereignty and territorial integrity, which began with its occupation of Crimea more than two years ago and expanded with substantial military on the ground and weapons support for armed separatists in eastern Ukraine," U.S. Ambassador to the UN Samantha Power told the council.
Russian UN Ambassador Vitaly Churkin countered that the Ukrainian crisis was provoked by a "coup d'etat with external support," and rejected claims that the source of conflict was "Crimea's union with Russia."
Moreover, Ukraine's case before the council was "very disappointing," he said, particularly because it lacked specifics on achieving peace.
"Over the entire crisis, the UN has been used as a propaganda platform," he said. "There is a lot of rhetoric but no specific plan about how to implement the Minsk agreement" forged in February 2015, he said.
Churkin said he hopes the cease-fire will hold over the upcoming holiday weekend.
"Easter is one thing that continues to unite us, Russia and Ukraine," he said.
Russia sought to circulate a resolution reaffirming the UN's commitment to the Minsk agreement, but failed to gain consensus approval because it also called for an investigation into the killing of Russian protesters in Odesa in May 2014 without mentioning violations by separatist forces.
Foreign ministers from France, Germany, Ukraine, and Russia are expected to meet in early May to try to further the peace effort outlined in the Minsk agreement.