Representatives from developing countries - a bloc of 135 nations including India and China - said they refused to participate in any formal working groups at the 192-nation summit until the issue was resolved.

The move was a setback for the Copenhagen talks, which were already faltering over long-running disputes between rich and poor nations over emissions cuts and financing for developing countries to deal with climate change.

Emissions reductions

It was largely seen as a ploy to shift the agenda to the responsibilities of the industrial countries and make emissions reductions the first item for discussion when world leaders begin arriving today, Tuesday.

"I don't think the talks are falling apart, but we're losing time," said Kim Carstensen, of the World Wildlife Fund. The developing countries "are making a point".

The dispute came as the conference entered its second week, but days before more than 100 world leaders including United States President Barack Obama were scheduled to arrive in Copenhagen.

Nothing happening

"Nothing is happening at this moment," Zia Hoque Mukta, a delegate from Bangladesh, told The Associated Press. He said developing countries have demanded that conference president Connie Hedegaard of Denmark bring the industrial nations' emissions targets to the top of the agenda before talks can resume.

"We are seeing the death of the Kyoto Protocol," said Djemouai Kamel of Algeria, the head of the 50-nation Africa group.

It was the second time the Africans have disrupted the climate talks. At the last round of negotiations in November, the African bloc forced a one-day suspension until wealthy countries agreed to spell out what steps they will take to reduce emissions.

- AP