Russia has been blocking a key technical panel whose work feeds into the 12-day negotiation round.
The Russians, supported by Belarus and Ukraine, are demanding a debate on how decisions are agreed at the UN Framework Convention on Climate Change (UNFCCC), the 20-year forum for addressing global warming and its impacts.
They say they sought to object to a deal at the UNFCCC's last big meeting, held in Doha, Qatar, last December, that saw an extension of the Kyoto Protocol.
"There's a big fight about how rules are agreed," said a source with a European NGO. "They obviously feel very sore about what happened there, and they are making a big deal about it."
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Other countries have expressed sympathy for Russia's argument for clarity on how UN decisions are adopted, but opposed its demands for a debate.
Decisions in climate talks are already crimped by national interests and would be even weaker if they have to be formally adopted unanimously rather than by the fuzzier format of consensus, said one delegate.
The spat has held up technical talks on how developing countries are meeting emissions goals, on forestry projects by developed economies and beefing up carbon trading.
A coalition of 850 green groups represented in the Climate Action Network today awarded Russia a symbolic "fossil" for the country "which does the most to block progress."
The decision at Doha hamstrings the sale of 5.8 billion tonnes of carbon credits that Russia had amassed under the first round of the Kyoto Protocol.
The wrangling in the panel, called the Subsidiary Body for Implementation, did not seem to badly affect other areas of the talks but has stoked worries of time pressure, the sources said.