 Several developing nations rejected on Saturday a climate deal worked out by US President Barack Obama and four major emerging economies, saying it could not become a UN blueprint for fighting global warming. Earlier, European Union nations reluctantly agreed to sign up for the accord worked out at a summit of 120 leaders by the United States, China, India, South Africa and Brazil -- meant as the first UN climate pact since the 1997 Kyoto Protocol. "I regret to inform you that Tuvalu cannot accept this document," said Ian Fry, delegate for the low-lying Pacific island state that fears it could be wiped off the map by rising sea levels. At an extra night session in Copenhagen after most leaders left, he said that a goal in the document for limiting global warming to a maximum rise of 2 degrees Celsius above pre-industrial times was too lax and would spell "the end for Tuvalu." Delegates of Venezuela, Bolivia, Cuba and Nicaragua also angrily denounced the "Copenhagen Accord," saying it would not help address global warming and was unfairly worked out behind closed doors at the December 7-18 conference. For any deal to become a UN pact it would need to be adopted unanimously at the 193-nation talks. If some nations are opposed, the deal would be adopted only by its supporters -- currently a group of major nations representing more than half the world's greenhouse gas emissions. Even backers of the accord conceded it was imperfect and fell far short of UN ambitions for the Copenhagen talks, meant as a turning point to push the world economy towards renewable energy and away from fossil fuels. Before leaving, Obama said the deal, which holds out the prospect of an annual $100 billion (61.7 billion pound) in aid for developing nations by 2020, was a starting point for world efforts to slow climate change. "This progress did not come easily and we know this progress alone is not enough," he said after talks with China's Premier Wen Jiabao and leaders of India, South Africa and Brazil. "We've come a long way but we have much further to go," he said of the deal, meant to prevent more heatwaves, floods, wildfires, mudslides and rising ocean levels. "The meeting has had a positive result, everyone should be happy," said Xie Zhenhua, head of China's climate delegation. European nations were lukewarm. "The decision has been very difficult for me. We have done one step, we have hoped for several more," said German Chancellor Angela Merkel. She had hoped that all nations would promise deeper cuts in emissions, mainly from burning fossil fuels, during the Copenhagen summit. A goal mentioned in some draft texts of halving world greenhouse gas emissions by 2050, for instance, was dropped. "I came here to Copenhagen wanting the most ambitious deal possible. We have made a start. I believe that what we need to follow up on quickly is ensuring a legally binding outcome," said Prime Minister Gordon Brown. "This is not a perfect agreement. It will not solve the climate threat to mankind.," said Swedish Prime Minister Fredrik Reinfeldt, whose country holds the rotating EU presidency. Australian Prime Minister Kevin Rudd called the deal "a significant agreement on climate change action. It is the first global agreement on climate change action between rich nations and poor countries." But he added "these negotiations have been exceptionally tough. The attitude taken by various countries in these negotiations has been particularly hardline." Many European nations had wanted Obama to offer deeper cuts in greenhouse gas emissions by 2020. But Obama was unable to, partly because carbon capping legislation is stalled in the US Senate. Washington backed a plan to raise $100 billion in aid for poor nations from 2020. The deal sets an end-January 2010 deadline for all nations to submit plans for curbs on emissions to the United Nations. A separate text proposes an end-2010 deadline for transforming the non-binding pledges into a legally binding treaty. Some environmental groups were also scathing. "The city of Copenhagen is a crime scene tonight, with the guilty men and women fleeing to the airport," said John Sauven, executive director of Greenpeace UK. Tensions between China and the United States, the world's two biggest emitters, had been particularly acute after Obama -- in a message directed at the Chinese -- said any deal to cut emissions would be "empty words on a page" unless it was transparent and accountable.