CHINA, India, South Africa and Brazil say a climate deal planned for 2020 would not be a "new regime", threatening confrontation with the US, which wants to eliminate a firewall between developed and developing nations.

The four nations reined in expectations for the Durban Platform in a statement released onTuesday following a meeting of the so-called Basic bloc in Beijing.

In Durban last December, the four states were party to an agreement that countries aim to hammer out by 2015 a new deal to fight climate change that will enter into force in 2020. "The Durban Platform is by no means a process to negotiate a new regime, nor to renegotiate, rewrite or reinterpret the convention and its principles and provisions," the countries said, referring to the United Nations (UN) Framework Convention on Climate Change.

The outcome of the discussions are governed by "in particular the principles of equity".

The statement may set up conflict with the US at two weeks of UN climate talks starting next week in Doha. At last year’s discussions, the US opposed inclusion of the concept of "equity" in the Durban mandate because lead envoy Todd Stern said it could be used to perpetuate a "firewall" that assigned developed countries binding emissions targets under the Kyoto Protocol Treaty, while setting no enforceable greenhouse gas goals for big developing countries.

After the Durban talks, Mr Stern was asked whether he had said "if equity’s in, we’re out," in the final discussions to craft the mandate.

"I might have, but that’s certainly the idea," he said. "We just thought that would be a distraction that would tend to drive people back into the old paradigm ." The "key element" of a new deal was "to include all the major players in the same legal system ."

China was willing to co-operate with the US to push climate change negotiation progress, Xie Zhenhua, vice-chairman of the National Development and Reform Commission, said in Beijing on Tuesday. "Developed nations should make greater efforts to cut emissions ," he said.

China and the US in July agreed that greater climate protection efforts were needed before a binding global treaty comes into force in 2020, joining nations at a meeting in Germany to acknowledge current pledges fall short.