European Union leaders agreed Friday to contribute to a $74 billion annual aid fund that would help developing nations adapt to climate change — but failed to set a firm figure for exactly how much the EU would pay.

"We are ready to offer if our partners deliver" and put up other financing that the EU says poor nations will need by 2020, European Commission President Jose Manuel Barroso said at the end of a two-day EU summit.

Swedish Prime Minister Fredrik Reinfeldt said Europeans "now have a very strong negotiating position" to seek tight greenhouse gas emissions cuts at United Nations talks in Copenhagen in December.

He said EU nations would not be required to contribute to the fund before 2013, bowing to demands by nine poorer EU member states strained by financial downturn.

Failure to agree on a figure now leaves the European Union without a firm promise of funding to tempt other nations — above all the world's two largest polluters China and the United States — into tight greenhouse gas emission cuts at U.N. climate talks in Copenhagen in December.

Oxfam said Europe's pledge is not enough and said both the EU and the U.S. should provide at least euro35 billion a year.