In a statement coinciding with the 10th annual UN climate change conference in Buenos Aires, Friends of the Earth Europe said the EU should "get rough" over the US rejection of the Kyoto Protocol.

"Substantially deeper (greenhouse gas) emission cuts are necessary to avert a catastrophe," Friends of the Earth climate campaigner Jan Kowalzig said.

"Yet the United States, as the world's largest emitter contributing a quarter of all emissions, still refuses to act," he said.

In Buenos Aires, the EU "must get rough with the United States, including threatening to introduce import taxes on energy-intensive US products as long as the US refuse to fight climate change", Kowalzig said.

Some 5,000 scientists, environmental activists and government officials from nearly 190 countries including the United States are attending the UN conference in the Argentinian capital.

A focus this year is preparing to implement the 1997 Kyoto accord, the world's most ambitious and complex environmental treaty.

Russia's ratification in November gave the protocol the final stamp of approval needed to go into force on February 16, after US President George W. Bush abandoned the agreement upon taking office in 2001.

US senior climate negotiator Harlan Watson said Friday in Buenos Aires that Washington was open to holding "informal gatherings" to discuss climate change, as long as they do not pave the way to post-Kyoto negotiations.

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