"In its current form, the Kyoto protocol places significant limitations on the economic growth of Russia," Andrei Illarionov, President Vladimir Putin's chief advisor on economic issues, told reporters.

His comments came as delegates from 180 countries met in Milan, Italy, to examine the future of the Kyoto accord, regarded by environmental protection groups as a key instrument in curbing global warming.

"Of course, in its present form, this protocol cannot be ratified," Illarianov said after Putin spoke to a gathering of Russian and European businessmen.

"It is impossible to undertake responsibilities that place serious limits on the country's growth," the advisor said, indicating that Putin had discussed the issue with the businessmen.

Illarionov argued that it would be unfair to Russia to curb emissions and stymie its own growth while nations that account for the bulk of global emissions refuse to join the pact.

He noted that "even some countries that seem to be suffering from climate change to a greater degree" had refused restrictions to be placed on their emissions.

Russian ratification of the Kyoto accord is needed to bring it into force worldwide, but since indicating at a world summit in Johannesburg last year that it would probably ratify the deal, Moscow has issued mixed signals on the issue.

At a conference on climate change in September, Putin said Russia was undecided on signing the protocol and would make its decision in line with its national interests.

Illarionov has been one of Russia's most noted opponents of the Kyoto accord which, signed as a "framework" agreement in 1997 and completed in 2001, requires industrialised signatories to trim output of carbon dioxide and five other types of carbon gases, most of which are a byproduct of fossil fuels.

With the world's biggest single polluter, the United States, rejecting the accord, the agreement can only take effect under its complex ratification rules after it has been approved by Russia's parliament.

In Milan, the spokesman for the UN Framework Convention on Climate Change (UNFCCC), Michael Williams, said the world body remains "optimistic that Russia will indeed ratify."

Moscow "has over the last few months sent mixed signals but Mr. Putin didn't rule out ratification last September," Williams told AFP.

In Brussels, a spokeswoman for EU Environment Commissioner Margot Wallstrom said: "It's nothing new.

"He said the same thing, almost, in September-October during the climate change conference in Moscow," Ewa Hedlund told AFP.

The European Commission warned meanwhile that the European Union was falling short of its own targets in the accord, and needed to urgently introduce new measures to correct the situation.

Some Russian officials have hinted at making ratification conditional on acceptance of its application to join the World Trade Organisation (WTO).

EU officials have refused linkage between the issues, though some have suggested that the Russian ratification of the accord would open up significant investment opportunities for European companies in Russia.

In principle, Russia is one of the major beneficiaries of the Kyoto accord, since the low level of pollution of its depressed post-Soviet industry gives it massive scope for trading in emission quotas authorised by the treaty.

Greenhouse gases are blamed for global warming by trapping the sun's heat rather than let it radiate safely out into space.

Most scientists fear that this could bring lasting harmful effects to the planet's delicate climate mechanism, though opinions differ on the seriousness of the situation.

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