The U.N. Security Council will no longer vote on Friday on a Russian-drafted call for aid access and civilian protection in Ukraine as Russia's U.N. envoy accused Western countries of a campaign of "unprecedented pressure" against the measure.

Diplomats said the Russian move would have failed with most of the 15-member council likely to abstain from a vote on the draft resolution because it did not address accountability or acknowledge Russia's invasion of its neighbor nor did it push for an end to the fighting or a withdrawal of Russian troops.

"Many colleagues from many delegations tell us about unprecedented pressure by Western partners, that their arms are being twisted, including blackmail and threats," Russia's U.N. Ambassador Vassily Nebenzia said on Thursday.

Speaking at a council meeting on Ukraine's humanitarian situation, requested by Western council members, Nebenzia said: "We do understand how difficult it is for those countries to withstand this kind of onslaught."

U.S. Ambassador to the United Nations Linda Thomas-Greenfield told Reuters after the meeting: "The only people who do arm-twisting around here are the Russians and they have to if they want to get anybody to support them."

Nebenzia said that Russia had instead requested the council meet on Friday - when the vote had been scheduled - to discuss "U.S. bio-laboratories in Ukraine using the new documents we obtained in the course of the special military operation."

At a U.N. Security Council meeting on the same issue last week, also requested by Russia, Thomas Greenfield said there are no Ukrainian biological weapons laboratories supported by the United States. The United Nations also said it had no evidence Ukraine had a biological weapons program.

Russia refers to its invasion of Ukraine as a "special military operation" targeting Ukraine's military infrastructure. Moscow denies attacking civilians.

The U.N. human rights agency has recorded 726 deaths, including 52 children, and 1,174 people injured, including 63 children, between Feb. 24 and March 15, U.N. political affairs chief Rosemary DiCarlo told the Security Council on Thursday. The "actual number is likely much higher," she said, without specifying who was to blame.

"Most of these casualties were caused by the use in populated areas of explosive weapons with a wide impact area. Hundreds of residential buildings have been damaged or destroyed, as have hospitals and schools," DiCarlo said.

"The magnitude of civilian casualties and the destruction of civilian infrastructure in Ukraine cannot be denied. This demands a thorough investigation and accountability," she said.

The World Health Organization has verified 43 attacks on healthcare in Ukraine that have killed 12 people and injured dozens more, including health workers, WHO Director-General Tedros Adhanom Ghebreyesus told the Security Council.

"In any conflict, attacks on healthcare are a violation of international humanitarian law," Tedros told the council, without specifying who was to blame.