The US said it opposed a climate deal that does not bring aboard both wealthy and developing countries as feuding over nations’ commitments dominated UN-led talks in Bangkok.

Todd Stern, the chief US climate envoy, said it was time to lay to rest the concept of a “firewall” between wealthy and developing countries that dates from the early 1990s – before the rapid economic growth of China.

“Many developing countries, including large ones, continue to be fixated on preserving the firewall between developed and developing countries,” Stern told a conference in New York, in a likely reference to China.

“We see this as both unjustified and incompatible with solving the problem,” he told the Bloomberg New Energy Finance Summit. “We are not going to be part of a new agreement with a fixed, bright-line, 1992-vintage firewall.”

The Kyoto Protocol required only wealthy nations to cut carbon emissions blamed for global warming, leading the United States to reject the landmark treaty.

The Treaty’s obligations run out at the end of next year and the EU has led calls for a new round of Kyoto pledges as a stop-gap measure.

Japan and Russia have led opposition to a new Kyoto round as the treaty does not involve China and the United States, the two largest emitters. China and other major developing countries would welcome an extension to Kyoto.

But Mr Stern insisted that China should be part of any future deal, saying it has surpassed France in emissions even on a per capita level.

“You cannot build a system that treats China like Chad when China is now the world’s second largest economy,” he remarked.

“Instead, you need to start with all the major emitters, both developed and developing, accounting for some 85 per cent of global emissions and build out from there,” Mr Stern said.

While seeking an agreement that involves all major economies, the US has played down the need for legally binding obligations.

The US has instead called for each nation to submit its own national plans – a bottom-to-top approach that would carry political weight but not necessarily legal obligations to cut a set amount of emissions.

“Don’t get me wrong, we are not opposed to such obligations if they genuinely apply to all the major players,” he added.

“But they are not really necessary; it is the national plans of countries, written into law and regulations, that count and that bind,” he said.

Legal obligations are an increasingly sensitive issue for the US. President Barack Obama has pledged that the US will do its part to fight climate change, but leaders of the rival Republican Party that won congressional elections last year are deeply skeptical on the issue.