United Nations climate talks are deadlocked after Europe said it could not accept a "watered down" road map to a new treaty which would not deliver a legally-binding global deal to cut emissions.
The over-running climate talks in Durban, South Africa, were thrown into disarray after the road map for a new climate treaty covering all major economies was altered to include options the European Union said were unacceptable to the majority of countries at the conference.
European ministers had been racing against the clock to secure the strong climate deal they had been seeking from the latest round of talks in Durban, which were due to finish on Friday night.
The EU wants the talks to agree a mandate to negotiate a new legally-binding treaty on global warming by 2015, covering all major emitters, in return for the bloc signing up to a second period of emissions cuts under the existing Kyoto climate deal.
As the talks dragged into the early hours of a second unscheduled night, EU climate action commissioner Connie Hedegaard warned the conference that "international problems require international legislation". She said that when there was a major global problem, then "voluntary means will not be enough to address that problem".
Ms Hedegaard told the conference that the EU was committed to a second period of emission cuts under Kyoto for at least five years, and said she did not think it was too much to ask that after that, all countries would be legally bound.
Earlier there had been a sense that the talks, although slow, were edging towards the deal for which Europe, backed by a coalition of some of the poorest and most vulnerable countries, was seeking.
However the options for the new legal deal were watered down to add a "legal outcome" to the existing possibilities of a "protocol or another legal instrument" - the language which was used in the mandate for negotiating the Kyoto Protocol.
UK Climate Change Secretary Chris Huhne said legal outcome could mean "absolutely anything and nothing" and represented a significantly watered-down version of the road map.
Earlier, Mr Huhne insisted a deal could be done in Durban. He said: "It's very clear that the vast majority of the participants in the conference are in favour of a good, balanced package which would give us a road map to a single over-arching protocol or legal instrument negotiated by 2015, entering into force by 2020."