Brussels - European Union leaders on Thursday agreed to reach a final deal on how to fight climate change in December after Polish threats of a veto were won over, officials said.

"The objectives remain unchanged and the calendar remains the same. It is now up to (European Commission) President (Jose Manuel) Barroso and myself to find solutions for those countries that have expressed their worries," French President Nicolas Sarkozy, who chaired the meeting, said.

"It was a very full discussion last night and this morning, but we agreed that the principles agreed in 2007 and 2008 are those to follow and we agreed that we have got to come to a decision in December," British Prime Minister Gordon Brown confirmed.

As the summit opened on Wednesday, Poland threatened to veto a declaration calling for a decision on the EU's proposed climate-change laws in December, saying that its concerns over the economic impact of the proposed laws had not been taken into account.

Seven other EU newcomers from Central and Eastern Europe backed that call, accusing the European Commission of not taking their earlier efforts on climate change into account.

And Italy joined the revolt, arguing that it would be too expensive to implement the laws given the present financial crisis.

But on Thursday morning the French government proposed a new resolution sticking to the December deadline but promising to take into account the "specific situation" in each member state. (dpa)