Russia blocked a British-drafted UN Security Council statement condemning the Syrian government attacks on the city of Aleppo, diplomats said.
It was the second time in a month that Russia objected to a western bid to slam President Bashar al-Assad's air assault against Syria's biggest city that has killed hundreds since December 15.
Aid groups say that Scud missiles and barrels packed with explosives and shrapnel have been dropped on schools, markets and hospitals in Aleppo, killing more than 700 people.
Britain circulated a draft press statement expressing "outrage" at the government attacks on civilians to the other 14 members of the council Tuesday.
The statement needs the agreement of all members to be released, and Russia objected, insisting all references to Aleppo be taken out, diplomats said.
So Britain withdrew the text for fear of seeing a tepid message put out, they added.
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Russia is a key backer of Assad and has used its power as a permanent council member to veto three legally binding resolutions on Syria since the war started in March 2011.
The United States proposed a non-binding statement on Aleppo in December, but Russia blocked it with what Western diplomats called "wrecking amendments" that would have watered it down.
The United States had doubts about releasing the new statement so close to the Syria peace conference due to start in Switzerland on January 22, diplomats said.
"The Security Council cannot remain quiet on this issue," said one Western diplomat of the new attempt. "The British draft is not anything that anyone should be surprised by."
In the statement, a copy of which was obtained by AFP, the council members "expressed outrage at the daily use of air strikes by the Syrian government against the city of Aleppo which have left over 700 dead and over 3,000 injured since December 15."
They called the attacks "cynical and systematic" in their disregard for international law banning attacks on civilians.
Russian diplomats would not immediately comment on the proposed statement.