OSLO (Reuters) - The United States is at odds with China and other developing nations by favouring a Copenhagen climate accord as the blueprint in 2010 for a stronger deal to fight global warming, documents showed on Wednesday. In a sign of hurdles ahead, developing nations are instead stressing UN texts worked out since 2007 to guide talks after the Copenhagen climate summit in December disappointed many nations by failing to agree a legally binding treaty. A 5-page US document outlining ideas for 2010 praises the non-binding Copenhagen Accord, the main outcome of the summit, as the basis for work due to culminate with a meeting of environment ministers in Cancun, Mexico, from Nov 29-Dec 10. We would welcome a further formalisation of the Accord in Mexico, according to the US submission dated Feb 22 and posted on the website of the UN Climate Change Secretariat. It says the accord led to landmark outcomes that...provide the basis for an agreed outcome in Mexico. The Copenhagen Accord seeks to limit global warming to below 2 degrees Celsius (3.6 degrees F) above pre-industrial times. It also promises aid for developing nations approaching $30b for 2010-12, rising to $100b a year from 2020. A document from China says that existing UN texts are the only legitimate basis for further negotiations. Elements of the Copenhagen Accord could be considered and where appropriate be built into negotiating texts, it says. Other major emerging nations including India make similar points. Saudi Arabia, which has often expressed fears that a shift to cleaner renewable energies will undermine its oil exports, is more blunt. Since the 'Copenhagen Accord has not been formally adopted, it has no legal status...and thus cant be used as basis or reference for further negotiations, it said. The UN texts are more vague than the Copenhagen Accord and lack firm targets after disputes focused on, for instance, the depth of cuts in developed nations greenhouse gas emissions by 2020. But developing nations reckon they are more balanced. A European Union document also emphasises existing UN texts but sees a role for the Accord. The Copenhagen Accord provides important additional input and guidance needed for the further elaboration and finalisation of these texts, it says.