"I had hoped for a more ambitious outcome -- on both finance and mitigation -- to meet the great challenge we face," Guterres said in a statement, adding that he is appealing "to governments to see this agreement as a foundation -- and build on it."

After two exhaustive weeks of negotiations, the final deal commits developed nations to pay at least $300 billion a year by 2035 to help developing countries green their economies and prepare for worse disasters.

That is up from $100 billion now provided by wealthy countries under a commitment set to expire -- and from the $250 billion proposed in an earlier draft Friday.

The deal "must be honoured in full and on time," Guterres said.

"Commitments must quickly become cash. All countries must come together to ensure the top-end of this new goal is met."

The UN chief said that "an agreement at COP29 was absolutely essential to keep the 1.5 degree limit alive."

"And countries have delivered."

He called on countries to deliver new economy-wide climate action plans "well ahead of COP30 -- as promised."

"The end of the fossil fuel age is an economic inevitability. New national plans must accelerate the shift, and help to ensure it comes with justice," he said, closing with a message to activists pushing for more to "keep it up."

"The United Nations is with you. Our fight continues. And we will never give up," Guterres said.