Brussels: Negotiators are working in Brussels and Copenhagen to come up with more climate change money for poor countries amid talks on a historic deal to control the world's greenhouse gases.

But by Friday morning, European Union leaders in Brussels had failed to muster pledges of $6.6 billion ($9.7 billion) they sought as the EU contribution to a three-year $30 billion ($20 billion) fund to help poor nations cope with climate change.

Eastern EU nations were resisting donating more due to the financial crisis.

Meanwhile, the climate conference in Copenhagen moves into a higher gear as top US and Chinese negotiators arrive.

More hectic bargaining is expected before the end of next week, when at least 110 heads of government will cap the two-year effort to reduce the emissions causing global warming.

Meanwhile, Britain will contribute along with France at least 1.5 billion pounds ($2.44 billion) to climate finance funding for 2010-2012, British Prime Minister Gordon Brown said on Friday.

"Our contribution will be at least 1.5 billion pounds over the three years and we also believe that Europe will be able to show today it will pay its share of the $10 billion fund," Brown said at a joint news conference with French President Nicolas Sarkozy at an EU leaders' summit in Brussels.

The EU leaders are hoping to agree on financing for developing countries to tackle global warming in the three years before any deal agreed at international talks in Copenhagen takes effect.

One EU source said member states had pledged a total of 1.8 billion euros ($2.65 billion) annually to help the developing countries during the three-year period, and another said that total was likely to reach up to 2.1 billion annually.

Brown said he expected the combined EU figure to be in excess of 2 billion euros by the end of the summit.