New York: Terming the Ukraine situation as the "biggest global peace and security crisis" in recent years, UN Secretary-General Antonio Guterres said the latest developments in Ukraine are testing the entire international system.

"We face a moment that I sincerely hoped would not come," he said at a media stakeout on Tuesday, adding "we must pass this test."

Deeply troubled by the latest developments regarding Ukraine, Guterres highlighted reports of increased ceasefire violations across the contact line and "the real risk of further escalation on the ground".

The Secretary-General again criticized Russia's decision to recognize the 'independence' of certain areas of the Donetsk and Luhansk regions.

"Let me be clear: The decision of the Russian Federation to recognize the so-called 'independence' of certain areas of Donetsk and Luhansk regions is a violation of the territorial integrity and sovereignty of Ukraine," the top UN official said.

According to Guterres, such a unilateral measure not only conflicts directly with the principles of the UN Charter but is also inconsistent with the so-called Friendly Relations Declaration of the General Assembly.

At this critical moment, the UN chief called for an immediate ceasefire and re-establishment of the rule of law.

"It is high time to return to the path of dialogue and negotiations. We must rally and meet this challenge together for peace, and to save the people of Ukraine and beyond from the scourge of war," Guterres said.