Copenhagen ? World leaders worked into the early morning hours to forge a political declaration for today’s summit on climate change, a document expected to envision emissions-cutting targets for rich nations and billions for poor countries but to fall well short of the goal of a legally binding pact.

A political deal would be seen by many as a setback, following two years of intense negotiations to agree on deeper reductions in the emissions of carbon dioxide and other gases largely blamed for global warming.

As President Barack Obama flew toward Copenhagen to join other presidents and premiers for the half-day of meetings and ceremony, a leading African delegate at the two-week U.N. climate conference expressed disappointment.

“It’s weak. There’s nothing ambitious in this text,” said Lumumba Di-Aping of Sudan.

The summit brings together the leaders of the two biggest polluting nations — Obama and Chinese Premier Wen Jiabao — with more than 110 other heads of state or government for the signing of the declaration.

The U.S. and China had sought to give the negotiations a boost on Thursday with an announcement and a concession.

On the U.S. side, Secretary of State Hillary Rodham Clinton said Washington would contribute to a climate change fund amounting to $100 billion a year by 2020, a move that was quickly followed by an offer from China to open its reporting on actions to reduce carbon emissions to international review.

Finance, money to help poor nations cope with climate change and shift to clean energy, seemed to be the issue where negotiators at the 193-nation conference could claim most success. Pollution cuts and the best way to monitor those actions remained unresolved. And negotiators also didn’t come to an agreement on an important procedural issue — just what legal form a future deal would take.

Yvo de Boer, the U.N.’s top climate official, tried to put a more positive light on the discussions, saying a political deal could be the key to later unlocking the negotiating stalemate on a range of issues.

“Leaders came here to lead, and that’s what they’re doing. They’re trying to reach an understanding on the key political components — and that’s good,” de Boer told The Associated Press well after midnight.

But he cautioned that a political declaration needed to include a deadline for agreeing on a replacement for the Kyoto Protocol, whose modest emission cuts for 37 industrialized nations expire in 2012. The U.S. rejects Kyoto and would be covered by a separate eventual agreement.

“You can reach an agreement here that sets out major political contours, a long-term goal, targets for industrialized countries, engagement by major developing countries, financing,” he said. “But people will want to see a clear deadline that turns that into a legally binding instrument.”

Delegates filtering out of the predawn discussions over the final document sounded disappointed.

“It’s a political statement, but it isn’t a lot,” said Chinese delegate Li Junhua.

“It would be a major disappointment. A political declaration would not guarantee our survival,” said Selwin Hart, a delegate from Barbados speaking for the Alliance of Small Island States, many of which are threatened by seas rising from global warming.

The reality was that a political deal was about all leaders could expect from a process that has foundered the past two weeks over growing distrust between rich and poor nations. Both sides blamed the other for failing to take ambitions actions to tackle climate change and bickered over a post-Kyoto legal framework.