The chief of the United Nations Antonio Guterres warned the General Assembly Wednesday that the world is "facing a moment of peril" over Ukraine's crisis with Russia.

"If the conflict in Ukraine expands, the world could see a scale and severity of need unseen for many years," he warned the body.

Russia on Wednesday sharply criticized Guterres' statements from the day prior on the situation in embattled eastern Ukraine.

"To our great regret, (Guterres) bowed to pressure from the West and made several statements on the events in eastern Ukraine that do not correspond to his status and powers under the UN Charter," Russia's Foreign Minister Sergey Lavrov said.

Guterres has to maintain neutrality and is "always obliged to advocate direct dialogue between conflict states," Lavrov said.

Guterres had condemned Russia on Tuesday for the escalation in the Ukraine conflict and called for respect for international law.

"When troops of one country enter the territory of another country without its consent, they are not impartial peacekeepers, they are not peacekeepers at all," Guterres said in New York in a rare open criticism of a U.N. veto power.

Russian President Vladimir Putin on Monday ordered a "peacekeeping operation" in Ukraine's Luhansk and Donetsk regions after recognizing the separatist regions' independence, paving the way to provide them more military support – a direct challenge to the West that will fuel fears that Russia could imminently invade Ukraine.

It came amid a spike in skirmishes in the eastern regions that Western powers believe Russia could use as a pretext for an attack on the western-looking democracy that has defied Moscow’s attempts to pull it back into its orbit.

Putin justified his decision in a far-reaching, pre-recorded speech blaming NATO for the current crisis and calling the United States-led alliance an existential threat to Russia. Sweeping through more than a century of history, he painted today’s Ukraine as a modern construct that is inextricably linked to Russia. He charged that Ukraine had inherited Russia’s historic lands and after the Soviet collapse was used by the West to contain Russia.

European Union leaders will convene at an extraordinary summit on Feb. 24 to discuss the Russia-Ukraine situation, Reuters reported late Wednesday.