Indonesia- A UN conference trying to lay the groundwork for a new climate change pact is unlikely to win any binding pledge by the United States to cut greenhouse gas emissions, its head said Friday.

Developing nations are also likely to refuse to commit to mandatory targets on cutting emissions blamed for global warming, said Yvo de Boer, executive secretary of the UN Convention on Climate Change. He insisted talks had started "very enthusiastically" on Indonesia's resort island of Bali, which on Friday evening felt the effects of a 5.9-magnitude earthquake off the coast, mildly rocking the convention centre.

Speaking to AFP, de Boer acknowledged the deep divides within the international community on how to tackle the problem of the world heating up, notably on whether countries should set binding targets. "I think all the delegations have understood the urgency, but I also think that none of the delegations have forgotten their national interest," he said on the sidelines of the meeting.

Delegates from nearly 190 nations are gathered for the December 3-14 summit, tasked with laying the groundwork for a new treaty to tackle global warming beyond 2012, when the Kyoto Protocol's first phase expires. Much attention has been focused on the extent of the reductions rich and developing countries need to make in greenhouse gases -- which trap heat and cause climate change -- to prevent a climate catastrophe.

A meeting of Kyoto parties in Austria in August recommended emissions cuts for rich nations of 25 to 40 percent by 2020, and green groups are keen for a similar figure to be mentioned in the final text of this UNFCCC conference.

But the United States, the only rich nation not party to Kyoto, has made it clear it will not commit to any such figures during this meeting, while Canada has said targets should include growing economies like India and China. De Boer said he thought the administration of US President George W. Bush may be willing to pledge to reduce emissions at home, but not on the world stage. "So the US is in favour of nationally binding targets, but not internationally binding targets," he said. Likewise, he said developing countries would also be unwilling to make any such pledges.

"I think that there is no developing country that is willing to sign up to binding targets," he added. "I think they are all willing to limit the growth of their emissions to the extent economically possible." Despite differences of opinion on the key issue of cuts, de Boer said he believed "most countries do want to walk away from Bali with an agreement that negotiations should be launched."

China meanwhile won plaudits at the talks Friday for leading a call for rich nations to make deep greenhouse gas emissions cuts.

"If you are looking at this week, here in the negotiations... China in particular has been more positive than previously anticipated," said Matthias Duwe, of the Climate Action Network Europe. Stefan Singer from green group WWF said that China knew tough targets for industrialised nations would "also mean that developing countries will also show enhanced action." Beijing has said that it would not back any new proposals that put binding curbs on the booming country, even though China ranks alongside the United States as the world's biggest emitter of greenhouse gas emissions.

Separately, an earthquake 261 kilometres (162 miles) southwest of the resort hosting the conference made floors and walls shake, but did not cause any panic at the conference centre. Many delegates had already left when the quake struck in the evening, while those who remained said they either did not feel anything or just a slight rumbling. No damages or casualties have been reported.