Russia says a new draft UN resolution supporting a plan for supervised independence for Kosovo is unacceptable and has hinted it could be vetoed.
Moscow wants ethnic Albanians and Serbs in Kosovo to reach agreement
The new text softens some of the original language and also proposes a new special envoy to help refugees who have left Kosovo, many of them Serbs.
But the Russian representative at the UN, Vitaly Churkin, told the BBC that the concessions changed nothing.
Kosovo has been administered by the UN since 1999, but remains part of Serbia.
The UN took over control of the territory following a Nato bombing campaign in 1999 targeting Serb forces.
Nato intervened to halt a violent crackdown by Serbia against ethnic Albanians in Kosovo, some of whom had taken up arms.
At the end of March, the UN special envoy for Kosovo, Martti Ahtisaari, unveiled a blueprint that would give Kosovo internationally supervised independence for an initial period.
At the same time, the proposals envisage extensive self-government for Kosovo's Serb-inhabited municipalities and continuing links between them and Belgrade.
Serbia has rejected the UN plan, but it has been broadly accepted by Kosovo Albanians.
Russia, a traditional ally of Serbia, has threatened to veto any UN Security Council resolutions supporting the plan unless Belgrade agrees to it.
The latest draft resolution introduced by the UK therefore made concessions to Russia.
The revised draft "supports" rather than "endorses" the provisions of Mr Ahtisaari's plan for supervised independence for Kosovo, and "calls for its full implementation".
The new text also "demands" rather than "underscores the importance" that Kosovo comply in full with obligations to implement UN-specified democratic standards.
Finally, there is a call for a special envoy to help refugees, many of them Serbs, who left Kosovo after the fighting eight years ago.
But Mr Churkin dismissed the changes, saying Moscow wanted more negotiations to see if the ethnic Albanians and Serbs in Kosovo can reach agreement.
"The introduction of this updated version of the draft has not changed anything as far as we are concerned," he told reporters.
"We should think in terms of continued effort to find a mutually acceptable solution to the future of Kosovo."
When asked by the BBC if Russia would therefore veto the draft resolution if it went to a vote, Mr Churkin would not be definitive, but hinted that his country might.
"You are getting well what is on my mind," he said.
The BBC's UN correspondent, Laura Trevelyan, says the US and Europeans, who support Mr Ahtisaari's plan for Kosovo, would like a vote to take place next week.
But other diplomats think the vote is unlikely to happen before the G8 meeting of world leaders in Germany on 6-8 June, our correspondent says.