* U.N. talks host urges delegates to accept pact
* Developing states say draft is too weak to save planet
* Acrimonious exchanges at climate talks
By Jon Herskovitz and Nina Chestney
DURBAN, Dec 11 The chairwoman of U.N. climate talks urged delegates to approve a compromise deal on fighting global warming in the interests of the planet, but an accord remained elusive on Sunday and rich and poor states traded barbs over the limited scope of the package.
South African Foreign Minister Maite Nkoana-Mashabane said the four separate texts represented a good outcome after two weeks of sometimes angry debates in the port city of Durban.
"I think we all realise they are not perfect. But we should not let the perfect become the enemy of the good and the possible," she told the conference.
Much of the discussion has focused on an EU plan designed to push major polluters -- from developed and fast-growing emerging economies like China and India -- to accept legally binding cuts in their greenhouse gas emissions.
EU negotiators had accepted "legal instrument" in one draft as a phrase implying a more binding commitment. But the latest version spoke of a "protocol, another legal instrument or a legal outcome", the sort of weak phrasing that almost collapsed the talks on Friday.
Asked if the latest language was acceptable, Karl Hood, who represents an alliance of 43 small island states, said: "No it's not. Never was and never will be. It's too broad a statement."
His alliance colleague MJ Mace, added: "You need a legally binding instrument. You have legal outcomes all the time. A decision is an outcome. You need something treaty like."
The discusions took an increasingly bitter turn as they headed into Sunday, a second extra day that made the negotiations the longest in two decades of U.N. climate talks.
Venezuela's climate envoy Claudia Salerno said she had received threats because of her objections to the draft texts.
"In the corridor, I have received two threats. One, that if Venezuela do not adopt the text, they will not give us the second commitment period," she said, referring to an extention of the Kyoto Protocol, the only global pact enforcing carbon cuts.
"The most pathetic and the most lowest threat... we are not going to have the Green Climate Fund," which is designed to help poor nations tackle global warming and nudge them towards a new global effort to fight climate change.
She did not say who had made the threat and delegates heard her allegation in silence.
Among the sticking points holding up a deal were an extension of the Kyoto Protocol. The draft text says the second Kyoto phase should end in 2017, but that clashes with the EU's own binding goal to cut carbon emissions by 20 percent by 2020.
U.S. VS CHINA AND INDIA
But behind the back and forth over language and technical details, the talks have boiled down to a tussle between the United States, which wants all polluters to be held to the same legal standard on emissions cuts, and China and India who want to ensure their fast growing economies are not shackled.
The fractious late night exchanges punctured the earlier mood of cautious optimism which had suggested agreement on the four separate accord in the package was possible.
Should the talks collapse on Sunday, that would represent a major setback for host South Africa and raise the prospect that the Kyoto Protocol could expire at the end of 2012 with no successor treaty in place.
Scientists warn that time is running out to close the gap between current pledges on cutting greenhouse gases and avoiding a catastrophic rise in average global temperatures.
U.N. reports released in the last month warned delays on a global agreement to cut greenhouse gas emissions will make it harder to keep the average temperature rise to within 2 Celsius over the next century.
A warming planet has already intensified droughts and floods, increased crop failures and sea levels could rise to levels that would submerge several small island nations, who are holding out for more ambitious targets in emissions cuts. (Reporting by Nina Chestney, Barbara Lewis, Agnieszka Flak, Andrew Allan, Michael Szabo and Stian Reklev; editing by Jon Boyle)
Our top photos from the past week.