European leaders failed Thursday to agree on how to fund the fight against climate change, leaving their legal beagles to try to hammer out a new proposal overnight, the EU presidency said.

Swedish Prime Minister Fredrik Reinfeldt, whose country holds the presidency, was still hoping to include some figures to flesh out the overall desire to help the developing world to minimise climate change and deal with its consequences.

"We need a clear mandate for Copenhagen," he told a press conference following the first day of talks at the two-day summit in Brussels, referring to global climate talks in December.

The EU prides itself in taking the lead in the fight against climate change, and has already agreed to cut greenhouse gas emissions by 20 percent by 2020.

However the leaders are split on how to fund those cuts and, in particular, how to fund climate measures in the developing world.

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

"The heads of state have left this to the lawyers and technical staff to try to hammer out an agreement," a source close to the EU presidency said.

"The new text will probably be proposed tomorrow (Friday) and we'll see where we land."

Italian Foreign Minister Franco Frattini said that France, Germany and Italy had urged the Swsedish EU presidency to content itself with a political agreement on climate funding, without announcing detailed proposals to the whole world.

"Our idea is to give the presidency a mandate to negotiate a political accord with the United States. We cannot make a unilateral commitment," he told reporters.

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

What the rest of the world proposes at Copenhagen is itself largely unclear.

The draft document causing such consternation contained several hard figures, such as the total 100 billion euros per year by 2020 which the European Commission estimates will be required to help the poorest nations tackle climate change.

Another draft estimate says that 22-50 billion euros per year of public money will be required.

European leaders are also seeking to agree on the size of the EU's contribution and where the money will come from..

"I hope that those figures... are going to be approved... so that we can go to Copenhagen showing that if the others move, if there is a deal, there will be financing for that deal for the poorest countries," EU Commission chief Jose Manuel Barroso told a press conference.

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.

"We are not going to give our agreement to a mechanism that says those responsible for the most emissions should pay the most," said Poland's Prime Minister Donald Tusk.

"In the current form, the burden-sharing proposal is not acceptable to us," added Hungary's Prime Minister Gordon Bajnai.

He said this view is also shared by Bulgaria, the Czech Republic, Latvia, Lithuania, Romania, Slovakia and Slovenia -- all newer members who have joined since 2004.

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, to be taken into account.

The EU is keen to enter international climate talks in Copenhagen starting December 7 speaking with a unified voice to encourage others, particularly the United States and China, to commit to swingeing emissions cuts themselves.