The first cracks appeared among developing countries at the UN climate talks yesterday, revealing divisions between emerging giants and nations most exposed to the ravages of global warming.

Tensions surfaced despite efforts to restore calm to the 12-day negotiations after a row over an early draft text proposed by Denmark, the conference's chairman.

The tiny Pacific island nation of Tuvalu drove a wedge in the bloc of developing nations by calling for discussions on an amendment to the Kyoto Protocol.

For the first time, it would require China, India and other fast-growing high-population nations to take on legally-binding commitments to slash CO2 pollution after 2013.

The move was swiftly opposed by the big developing countries, ripping open a faultline within the so-called G-77 plus China bloc of 130 nations.

Until now, the group has stood by a diplomatic axiom that has prevailed since the UN climate convention came into being in 1992: rich countries caused global warming, and it was their responsibility to fix it.

According to this stance, only rich nations should be required to sign up to legally-binding emissions curbs under Kyoto.

But small island states and least developed countries - which supported Tuvalu's move - have become increasingly worried that such an approach will not rein in a dangerous surge of emissions in the future.

This pollution will come not from the industrialised world but from the high-population economies of China, India and Brazil.

Taukiei Kitara, head of Tuvalu's delegation, said that the proposed constraints "would mostly remain on developed countries but also, partly, on big developing economies as well."