POZNAN, Poland — The country will refuse to sell carbon-emissions credits to other nations, removing from the market the biggest single pool of licenses to release greenhouse gases under the Kyoto global-warming treaty, a government official said.

The country will hold the credits beyond the Kyoto Protocol's 2012 deadline, Viktor Blinov, deputy chief of Russia's delegation to United Nations climate talks in Poland, said Tuesday.

Instead, Russia will use them to comply with a successor treaty that is being negotiated.

The comments may help quell speculation about what Russia will do with credits that cover releasing 3.3 billion tons of carbon dioxide through 2012, or about 18 months of greenhouse-gas emissions from all the factories and power plants in the 27-member European Union, according to World Bank estimates.

Kyoto credits are sold over the counter without published prices. Russia's holding is worth 46 billion euros ($58 billion) based on a similar UN-certified credit trading in London. Global carbon trades totaled $64 billion in 2007, the World Bank said.

"We've got more allowances than we need," Blinov said. "These extra emissions should be banked for the next period," regulated by a new pollution-limiting treaty, to give Russia's economy more room to develop, he said.

Under the treaty, 37 nations were given greenhouse-gas emissions targets for the 2008 to 2012 period and were granted pollution credits that can be sold if they undershoot the goals.

As of 2006, output of the gases in Russia had fallen 34 percent from 1990, according to the UN.

A UN-certified emission reduction for December, a CO2 allowance similar to a Kyoto credit, was unchanged at 14.10 euros ($17.83) a ton on the European Climate Exchange on Wednesday.

Refusing to sell credits, called "assigned amount units" under the Kyoto treaty, will shrink the potential pool of CO2 licenses that might be bought by nations such as Italy or Spain, which are on track to exceed their credits granted under Kyoto.

Russia, the world's biggest natural-gas producer, may withhold AAUs because it does not want to lower the price for emissions, which would make it relatively cheaper for power utilities to burn coal instead of cleaner-burning natural gas, which needs about one-half the permits.