RUSSIA accused Canada on Thursday of childishly annotating a letter it sent at the United Nations seeking support for its draft resolution on providing aid access and civilian protection in Ukraine, which Ottawa reacted to with pointed comments.

In a spat on Twitter, Canada's UN mission added multiple remarks to the March 16 missive from Russia's U.N. ambassador, Vassily Nebenzia.

The U.N. Security Council will no longer vote on Friday on the draft resolution.

Diplomats said it would have failed with most of the 15-member council likely to abstain from a vote on it because it did not address accountability or acknowledge Russia's invasion of Ukraine or push for an end to the fighting or a withdrawal of Russian troops. 

In the spat on Twitter, Canada's UN mission annotated one part of the Russian letter that read: "Like other members of the international community, we are gravely concerned about its deterioration."

Canada's UN mission crossed out the first few words and changed the rest to read: "We are not gravely concerned about its deterioration," and inserted at the end "because we are the primary cause."

In a later section, Canada asked: "Do you think the UN membership actually believes this?" On the final page Canada suggested part of an alternative end: "We want you to know just how little we care about the human life we have destroyed."

Dmitry Polyanskiy, first deputy permanent representative of Russia to the United Nations, hit back on Thursday:

"Thank you @CanadaONU for this kindergarten-level Russophobic libel!" he wrote on Twitter.

"It only shows that your diplomatic skills and good manners are at lowest ebb and gives an idea why your country’s bid for a non-permanent seat in #SecurityCouncil was voted down twice in 20yrs by UN membership," Polyanskiy said, adding a thumbs-down emoji.

Relations between Russia and several Western nations continue to plummet to new lows since the Kremlin launched its invasion of Ukraine.

Russian President Vladimir Putin says he is engaged in a "special military operation."