Key developing states rallied to an EU roadmap for a binding pact to fight global warming on Friday, but draft agreements emerging at U.N. climate talks showed deep divisions remained and Europe said the negotiations could yet collapse.

The EU plan sets a 2015 target date for a new deal that would impose binding cuts on the world's biggest emitters of heat-trapping gases, a pact that would come into force up to five years later.

EU Climate Commissioner Connie Hedegaard said Brazil and South Africa, whose growing economies are heavy polluters, now supported binding cuts to emissions of the greenhouse gases that cause rising sea-levels and increasingly extreme weather.

But speaking to reporters in the South African port of Durban she said an agreement was far from certain before the talks' scheduled end on Friday.

The success or failure of Durban hangs on a small number of countries who have not yet committed to the (EU) roadmap and the meaningful content it must have, Hedegaard said.

If there is no further movement from what I have seen until 4 o'clock this morning, I don't think there will be a deal in Durban. That's what we are faced with.

A draft text emerged that could legally bind more than 30 industrialised countries to cut emissions under a second phase of the Kyoto Protocol -- the only global pact that enforces carbon cuts.

However, it would likely only be adopted if all emitters agreed to take on legal targets in a separate, broader agreement that would bind China, India and the United States.

Climate experts doubted the wording of the second text would be acceptable, as it merely referred to a legal framework, stopping short of a legally binding treaty that the European Union and many developing countries are demanding.

In the next years we will not have a legal regime, nothing will control the big emitters, the developed countries. without that framework everyone can do what they want, said Rene Orellana, chief negotiator for Bolivia and part of the ALBA group of Latin American nations, said if the proposed texts went through.

This is not just the death of Kyoto, it's the death of the planet. We need a regime to control emissions, to enforce compliance, he said.

Critics also complain the texts are unclear about when emissions cuts must come into force and how deep the reductions will go.

UNDER PRESSURE

The EU strategy at the conference has been to forge a coalition of the willing designed to heap pressure on the world's top three carbon emitters -- China, the United States and India -- to sign up to binding cuts. None are bound by the Kyoto Protocol.

Washington says it will only pledge binding cuts if all major polluters make comparable commitments. China and India say it would be unfair to demand they make the same level of cuts as the developed world, which caused most of the pollution responsible for global warming.

Many envoys believe two weeks of climate talks in Durban will at best produce a weak political agreement, with states promising to start talks on a new regime of binding cuts in greenhouse gases. Anything less would be disastrous, they say.

U.N. reports released in the last month show time is running out to achieve change. They show a warming planet will amplify droughts and floods, increase crop failures and raise sea levels to the point where several island states are threatened with extinction.

The Durban talks are scheduled to wrap up on Friday but are widely expected to extend long into the night and even Saturday.

The dragging talks frustrated delegates from small islands and African states, who joined a protest by green groups outside as they tried to enter the main negotiating room.

You need to save us, the islands can't sink. We have a right to live, you can't decide our destiny. We will have to be saved, Maldives' climate negotiator Mohamed Aslam said.

Karl Hood, Grenada's foreign minister and chairman of the 43-nation Alliance of Small Island States (AOSIS) whose members are in the frontline of climate change, said the talks were going around in circles.

We are dealing with peripheral issues and not the real climate ones which is a big problem, like focusing on adaptation instead of mitigation, he said. I feel Durban might end up being the undertaker of UN climate talks.

(Additional reporting by Andrew Allen, Agnieszka Flak, Barbara Lewis; editing by Jon Boyle)