The EU Environment Commissioner, Ms Margot Wallstrom, has accused the US of working to undermine the prospects of implementing the Kyoto Protocol on Climate Change.
As delegates from more than 160 member states began arriving here for the latest round of negotiations, Ms Wallstrom said the US was using its influence over countries such as Japan in an effort to scupper a deal.
"They (the Americans) have an interest in delaying us and trying to convince the others," she said in an interview with European Voice. "But, of course, it would be more difficult for them if the rest of the world agrees in Bonn."
The US President, Mr George W. Bush, pledged at his Gothenburg summit with EU leaders not to obstruct progress at the resumed session in Bonn.
"I wish I knew what that man thinks," the EU Commissioner said of Mr Bush. Last March, after he announced that the US was pulling out of its treaty commitment, Ms Wallstrom was to the fore in denouncing the President's action.
But the former Swedish environment minister is not alone in believing that the US has been putting pressure on Japan not to go ahead with ratifying the protocol agreed in Kyoto nearly four years ago.
Yesterday, the World Wide Fund for Nature explicitly urged the US delegation at the Bonn talks to honour Mr Bush's promise in Gothenburg and refrain from obstructing progress towards agreement on how to make the Kyoto Protocol work.
Given that the US has turned its back on adopting the protocol's legally binding targets for reducing greenhouse gas emissions, Ms Jennifer Morgan, director of WWF Climate Change campaign, said the eyes of the world were now on Japan.
Though the Japanese Prime Minister, Mr Junichiro Koizumi, said at the weekend that his government would negotiate "until the last minute" in an effort to salvage Kyoto, he believed it was unlikely that agreement would be reached in Bonn.
"The credibility of Japan as a responsible global actor is clearly at stake," said Ms Morgan, adding that it would be "tragic if Japan's vaccillation killed a vital UN agreement that bears the name of its ancient capital".
Mr Bill Hare, climate policy director of Greenpeace, said Kyoto "can only survive if Japan abandons its pretence of attempting to turn around Bush's hardline rejection of the protocol and commits itself to ratify" the terms on offer.
He also referred to reports that Japan is seeking to amend the protocol's targets and timetables for reducing greenhouse gas emissions. "If this is true, Mr Koizumi is making a terrible mistake in seeking, somehow, to appease Mr Bush."
Mr Jan Pronk, the Dutch Environment Minister, who is chairing the Bonn summit, put forward a suggestion earlier this month that it might be possible to delay the timetable on cuts by two years beyond the Kyoto target date of 2012.
Such a compromise, which is intended to bring the US back on board, has received support from some EU countries, notably Britain. But it is strongly opposed by others, who believe that the EU must continue to stand up to the US.
Though rejecting the Kyoto Protocol, the US is participating in the Bonn Summit and will be paying particular attention to the outcome of the negotiations that might affect trade or create precedents for other international agreements.
The reason the Bonn Summit is happening at all is because last year's scheduled climate change talks in The Hague broke down over irreconcilable differences between the EU and the US over how Kyoto should be implemented.
The EU, backed by the environmental lobby, accused the US delegation in The Hague of introducing a large number of loopholes to avoid making serious cuts in its own emissions.
If the US now succeeds in persuading other industrialised countries, such as Japan, to refrain from ratifying the average 5.2 per cent cut in emissions required by the protocol, then Kyoto will be "dead in the water", as the Australians have put it.
