BRUSSELS: EU leaders have agreed to enter world climate talks arguing that poorer nations will need 100 billion euros a year by 2020 to tackle global warming, but failed to set levels for Europe's contribution, a draft text said Friday.

"The EU is ready to take its fair share of the global effort by setting an ambitious mitigation target, allowing for offsets and providing its fair share of public support," said the text, drafted for a summit in Brussels, without saying how big that share might be.

"The European Council endorses the (EU) commission estimate that the total net incremental costs of mitigation and adaptation in developing countries could amount to around 100 billion euros annually by 2020," the draft said.

EU leaders broke off talks Thursday night, unable to agree on how to share out the burden of helping poorer states reduce carbon dioxide emissions, just weeks ahead of the Copenhagen climate summit starting December 7.

EU drafters and legal experts worked overnight in a bid to overcome objections, mainly from poorer central and Eastern European nations.

According to the revised draft, which could yet change during the second day and final day of the summit, they agreed the baseline figure should "be met through a combination of (developing nations') own efforts, the international carbon market and international public finance".

Other figures were included in the draft text, including 22-50 billion euros by 2020 which the leaders believe will be required in international public funding as part of the overall 100 billion.

However when it came to the thorny issue of which European countries should fork out what amounts, the draft text was mute.

The 27-nation bloc prides itself in leading the fight against climate change, and has already agreed to cut greenhouse gas emissions by 20 percent by 2020, but many fear its leadership role could be compromised without a burden-sharing deal.

Europe is keen to enter international climate talks in Copenhagen speaking with a unified voice to encourage others, particularly the United States and China, to commit to swingeing emissions cuts.

The European Union has said it is willing to increase its own promised emissions cuts to 30 percent if the rest of the developed world does likewise.

But EU nations are split on how to fund their common ambitions.

Central and eastern European nations, led by Poland, are reluctant to give aid to other countries, such as Brazil and China, which they deem to be no poorer than the poorest in Europe.

Others, like Germany, feel it premature to go into too much detail before Europe knows what the rest of the world proposes at the international climate talks.

In an internal EU document, the leaders said "the contributions of EU member states should take account of their capacity of the less prosperous member states to contribute".

It added that "according to their respective economic and financial situation", the states would commit to financing the efforts of developing nations in the short term, from 2010-2013.

A previous draft said 5-7 billion euros in annual fast-track funding would be required, but the revised version stressed the figure "will be determined in the light of the outcome of the Copenhagen conference" rather than before it.

EU foreign policy chief Javier Solana said figures could be agreed but kept private "as a tactic for the negotiations in Copenhagen".

Poland, heavily reliant on coal-fired power stations, and eight other new members from eastern Europe are above all anxious to ensure that the burden of funding is not allotted according to national CO2 emission levels but mainly on GDP levels.

The eastern European states also want the large amount of polluting rights, which they have not used up due to the collapse of industry since the break-up of the Soviet Union, taken into account.